Hmm, have you done any virus scans or spyware scans or any type of scan or even deleted any files between this morning and now?

EDIT: I just read up that you might need to install the latest XP update.

to check if you have it go to Start then Control Panel then go on Add or Remove Programs check mark the Show Updates button and scroll to the bottom and what ever does not say installed on xx/xx/xx then click on it then follow the link.

Im using Vista at home. The other PC's I used were running XP and it has previously worked on them too. Looks like its dead

Sounds like the pen drive is knackered. Id replace it. They are as cheap as chips nowadays.

How long have you had it for?

Only about a year or so, maybe year and a half. I will replace it if need be, but would rather get it working if possible because there may be some files I want on it. Most stuff backed up I think there was part of a piece of coursework on there which I don't have elsewhere but doesn't matter too much because I have handed that in.

I suggest you do, sorry for your lose. I suggest you get a better company this time. SanDisk is not the best. If your planning on spending around 30 bucks this is the best you could get. HP V140W 4GB USB Flash Drive - 15MBsec Read, 4MBsec Write, USB 2.0, BlueGray V140WA4GB in Canada at TigerDirect.ca