Sounds virusy. If it is you'll need to reinstall and will need to borrow a windows CD.
Does it have an XP sticker on the side. You might need a particular CD for it to work.
You could get someone to remove the hard drive, plug it into another machine as a slave and scan for viruses to see if it detects anything.
Are you techie or not ... you'll need to be to fix it yourself.