PC doctor

: My CD-Rom drive light flickers continuously when I have inserted aorgotten passwords, irritating flickering lights and slothful processors. CD-ROM. As it is right in my line of sight this is extremely distracting. What's more, whenever I put a disc in my drive, my PC tries to install files or opens a program. What can I do to stop these annoyances?

Balvinder Chhina, Crawley.

A: The CD-ROM LED lights up when the drive is reading a disc - it is a signal that data is actually being transferred from the CD-ROM. You can't stop it doing this except by opening the drive and physically disconnecting the LED - this would be difficult and invalidate your warranty. Although we find the light useful, as it means you know that the drive is actually accessing data on the disc, if it is that much of an irritant we'd suggest putting a bit of insulating tape over the LED or simply moving your PC so you don't look directly at the drive.

Windows 95 and 98 incorporate an AutoPlay feature for CD-ROMs - Microsoft thought it would be helpful to users if CDs played automatically as soon as you put them into the drive. However, this can be annoying. To turn Auto-Run off, right-click on My Computer, choose Properties and go to the Device Manager tab. Select your CD-ROM drive, click on Properties and then uncheck the box by Auto Insert Notification.

If you still want most CDs to run automatically, and only disable AutoPlay for one disc, just hold down Shift while you insert the CD-ROM and it will not play.

Q: I can't access the BIOS Setup program on my Olivetti-PC because my son has password-protected it. He now tells me that he can't remember the password, leaving me with a bit of a problem. Is there any way that I can get into Setup without knowing the password.

D Walton, Manchester

A: If your son has just turned on password protection, he may not actually have set a password himself - all BIOS chips are pre-programmed with a default password. This is normally related to the manufacturer's name, which appears in the top left-hand corner of your screen as you start up your PC.

If your BIOS is from AMI, type in AMI; if it is from Award, try AWARD_SW - you get the picture. Unfortunately, this is a case of trial and error as there may be variations even between BIOSes from the same manufacturer. It's worth a try though, as if you are successful you will preserve all your current BIOS settings.

Anything else you try will erase all your BIOS settings so you will have to re-enter them manually or rely on your PCs autodetection facilities - these are normally quite good though. As the BIOS settings are stored in a battery-backed chip, removing power to this will erase all the settings - including the password.

Switch off the power and remove your PC's case. Touch part of the metal frame to earth yourself, and then look for a watch battery in a holder on the motherboard (the main circuit board). You may have to disconnect some cable or remove some cards to get to it - take a careful note of where they plug back in.

If you spot the watch battery, remove it and wait for half an hour or so - this will allow the chip to lose all its current settings. Then replace the battery and try restarting your PC.

If you can't see a watch battery, you may have a rechargeable battery or one that is soldered to the motherboard. It is possible to remove or discharge this but, unless you know what you're doing, we'd recommend you seek help from a computer repairer as you could damage your system.

Q: I am having problems with my scanner - I have a SCSI flatbed scanner. It is temperamental - sometimes it works and sometimes it doesn't. I can't see any rhyme or reason to it and am at my wits' end.

N Field, Suffolk

A: Without further details of your scanner model it's difficult to be specific, but SCSI connections are normally very reliable. However, you need to watch two things. First, switch on the scanner before you boot up your PC - this allows both the computer and Windows to recognise that the device is attached.

Second, all SCSI 'chains' - several devices linked together - need to be terminated at each end. Both your scanner and your SCSI card should detect this automatically, but some do not. Check the jumper and switch settings on the card and the device, and switch termination on if you can. If this doesn't help, it may be worth buying an external terminator which plugs into the other port on your scanner as these can be more reliable - any good computer dealer should be able to help.

Q: I have an ageing 486 PC which, though it runs Windows 95, is rather slow. I have been told that I could fit an OverDrive processor to increase its speed, but I am unsure what this is. Could you tell me how to get hold of one?

James Snelling, Essex

Q: About two years ago, I bought a P120 machine. Now, more and more games and applications need a faster processor to run - they often demand a P133 or even a P166. Can I just buy a new processor and then fit it into the old socket, or is it more complicated? I have seen an OverDrive processor which could take my PC to a 200MMX, but at #150 this seems expensive when compared to a normal chip.

Paul Higgs, London

A: OverDrive processors supplied by Intel and equivalent devices from other manufacturers are designed to allow an old PC to use a processor that really shouldn't be fitted. Intel OverDrive processors allow you to upgrade a 486 to a 486DX4-100 or a Pentium PC up to a P200MMX (though these are no longer made, you may still find one for sale), while equivalent chips from companies such as Kingston Technology use AMD processors to upgrade 486s to Pentium-class performance and Intel chips to take Pentiums to 233MHz.

They are more expensive than ordinary chips because, although you might be able to physically fit a new processor to your old motherboard, it would not work. Because the Pentium MMX processor works at a different voltage to the classic Pentium chip, the OverDrive must include extras like a voltage regulator. All these chips are available from mail-order suppliers, who will be able to advise you on which is the most suitable.

Intel: 01793 403000

Kingston Technology: 0800 435978

Q: Because my PC has only 16Mb of RAM, many of my programs will not run and come up with an error box that says I have insufficient memory. Recently, I heard that Windows 95 uses some RAM, so I wonder if I could run these programmes under MS-DOS. However, if I try to open a file under DOS I always get the error message 'Invalid directory'. Can you tell me how to start a program in DOS?

Nitin Boojnan, South Norwood

A: It may cost a bit of money - probably around #30 - but your best bet is simply to add more RAM to your computer. Check in your PC's manual to find the details of the chips you need, almost certainly two 72-pin SIMMs. Any mailorder supplier will be able to furnish you with these - two 8Mb modules would give you a total of 32Mb. This would give your PC a huge speed increase in all applications, both Windows and DOS. What's more, RAM is simple to fit, while it can be difficult to get to grips with all the intricacies of DOS.

Although Windows 95 offers a graphical interface which is relatively easy to use and navigate your way around, it still uses the underlying DOS directory structure. If you try to find a piece of paper in a filing cabinet, you must first choose the right cabinet, then the right drawer and finally the right folder before you retrieve your document. In the same way, to find a file in Windows you must open a series of nested folders - directories - by clicking on them before you get to your destination, while in DOS you have to open exactly the same directors manually.

However, because the DOS interface is text-based it is much harder to follow and to keep track of exactly where you are. What's more, you need to know - or at least be able to follow - the full pathname of any file you want to open.

When you boot into DOS, you will see a prompt which tells you which folder you are currently in and what drive it is on. To switch to another folder, type cd \pathname, replacing pathname with the full name of your folder. If it is on another drive, you will first need to switch to that drive - simply type driveletter: (to select your hard disk, this will normally be c:, while your CD-ROM drive will normally be d:).

If you want to find out which files are actually contained in a folder, use the dir command while you are actually in that folder. This will produce a list of every file - if there are too many to fit one screen then typing dir /p will break up the list and allow you to read it.

Once you've actually found the file you want to run, simply typing its name will open it, though bear in mind that only games and programs which support DOS will work.

If you have booted into DOS then Windows-only software will simply not run and may crash your computer. If you are running a DOS prompt from within Windows, then packages like Word and Excel will open - but in Windows not Dos. This won't help your memory problem.

Bear in mind too that DOS can't cope properly with file or folder names longer than eight characters. Any name longer than this will be truncated by DOS. Although each truncation is unique, it is confusing as it consists of six characters followed by a tilde and a number - see our screenshot!

The PC doctor regrets that he cannot provide readers with individual replies or answer queries over the telephone, but if you have a question or problem you want to share with other readers, write to PC doctor, WhatPC? Editorial, VNU House, 32-34 Broadwick Street, London W1A 2HG or e-mail whatpc@vnu.co.uk.

The writer of EVERY letter published will receive a FREE Microsoft IntelliMouse and a choice of Microsoft Bookshelf, Publisher 97 or Money 97. Please state which you would prefer.

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