Carol Vorderman's Internet column: www.help.desk.

Q I SAW a message on my screen saying the c drive was being defragmented. I stopped it. What does this mean and how did it start?

Graeme Holmes 

A IT'S not bad news! The files on your hard drive are stored in clusters and a file may consist of dozens (thousands even) of them.

These are stored in a chain on the disk. Whenever you want to open a file, your computer has to gather all the clusters that make up that file. As long as the clusters are gathered together in a chain, it's a fast job and the file opens quickly.

But if you edit a file and make it bigger by filling more clusters, the extra ones have to be added to the chain, which may be a long way from where the bulk of the file was placed.

Pretty soon, your hard disk has pieces of file scattered everywhere and your computer has to work harder to find all the pieces of a file when it's needed. In other words, your hard disk is "fragmented".

Defragmentation simply works through the clusters on your disk, gathering all the pieces of individual files together again, which will speed up your computer. This is a "housekeeping" process that Windows runs automatically every week or so when your computer has been idle for a few minutes.

QTHERE are always warnings about meeting people from newspaper dating sections, but there is nothing on the internet about personal safety. I have heard of ladies going to meet men they have been "chatting" to on the web. Many don't realise that people can have lots of different screen names. What should you do if you want to meet someone in person?

Jenny Williams 

AA GOLDEN rule of internet use is: All you know about someone is what they've chosen to tell you.

If you want to see someone you've chatted to online - meet in public, in daylight, and preferably with a friend in tow. Never give your address, phone number or place of work to someone you've only ever "met" online.

This is doubly important where children are concerned. They may innocently tell someone their address or school. We ask children not to talk to strangers in the street, but don't always remember our kids may talk to them online.

We don't want to stop children going online, but we need to educate them and new users about the realities of Internet use.

QUP UNTIL now, when I have been on the home page, I have been able to read my emails by clicking on to Mail on the Tool Bar and selecting Read Mail from the menu. When I do this now, it does not take me to Outlook Express as before. I can't understand why this has changed. I recently installed Office 97 and wonder if this has anything to do with it.

John McDonald 

AMICROSOFT Office sets Outlook as your default email program, rather than Outlook Express. In Internet Explorer, choose Internet Options from the Tools menu, click the Programs tab, and open the drop-down list beside "Email". You'll find Outlook Express included on that list, and you can select it to reinstate it as your default mail program.

QI CHECKED my computer and found a whole list of cookies all about 1Kb in size. Can they be deleted safely or are they just going to increase in number and take up more HDD space? There was also a file at the bottom of the list called index, what is this for?

Brian Gookey

ACOOKIE files can be deleted in the same way as any other file, butthey're also going to increase as you visit more sites (or revisit the same sites) that use cookies. The index file shouldn't be deleted and usually resists all attempts to delete it.

It's used by Windows to match cookie files to particular web sites. Internet Explorer has settings that let you limit or prevent cookie use (Tools, Internet Options, Security, Custom Level) but refusing cookies may prevent you from accessing certain sites or reduce their usefulness.

GOT Internet problems? Got a story? email me at [e-mail] or write to Carol@Mirror, The Mirror, 1 Canada Square, London E14 5AP. Don't forget our website at: www.mirror.co.uk