How do I de-, and, indeed, frag?

[policywonk]

Do I need to back things up first?
Will I have to reinstall all software afterwards?
How long does it take?
Will I need to wear protective glasses?
Anything else I should know?

blimey do we still need to defrag things?

You don't need to back things up, although of course you should be backing up important files regularly anyway, so maybe you should just as a precaution. You won't need to reinstall anything - it will only move files which can safely be moved, so won't affect any software.

It takes as long as it takes - depends on the size of the drive and how fragmented it is, so it's a "length of a piece of string" question.

And you should always wear goggles and a facemask whenever you're using a PC - didn't you know that? How else do you protect against the viruses?

No need to back up. Just press defrag and leave for a few hours. You won't need to reinstall anything afterwards.

AFAIK, with Vista you don't need to do this anymore. Or rather you do but the operating system does it by itself without telling you.

Thank you.

I will set it going tonight before I head off to the PTA quiz

If I'm not back here within 24 hours will somebody inform the emergency services please.

One thing to remember about defragging is that you need a certain amount of space to do it in - I was sorting out an ageing tablet notebook for one of the teachers on Friday; we don't have the discs for the tablet version of XP so I can't reformat, which is hat it really needs and it only had 7% of the hard drive free. I had to delete an awful lot of crap vitally important teaching tools before I got the 15% space it needed.

Can I set my PC to defrag overnight? or do I need to be available to click ok/accept/etc at any point?

You should be ok to set it running overnight. Can't remember anything popping up which you had to press.

Well, I've left the tablet to defrag over the weekend! I can't remember having to click anytime apart from the initial setup, though it did take a short while the first time I tried to discover it wasn't going to be able to do it.
You may get a dialogue box if it can't complete the task for some reason, but it'll just sit there until you come back to it, assuming your power supply is OK.

Thanks, I'll try to remember to do it before I go to bed tonight.
Its a desktop so hopefully no power supply issues (knowing my luck there will now be a power cut tonight!)