I agree with vhelpfulguy, a firewall would be a good start. However you should also get yourself some anti-virus software and run a spyware scan. If you search for those phrases on this site, you'll find plenty of good advice. I would recommend that you install AVG for anti-virus and run SpyBot Search'n'Destroy for Spyware:
We had a similar thing at the beginning of the year and I phoned microsoft and the technician talked me through lots of stuff which seemed to work in the end cos now it's fine.
Thank you ALL for your advice and sugestions. But I am going to wipe the Hard Drive, and start again. Luckily I have all "my doc's" on an external hard drive, so it shouln't be too hard a job.
THANK's AGAIN ALL.
I had to clear my 'comp:', a had a bit of trouble, called in an engineer, and found I needed a new grafic's card.
AGAIN!
THANK'S TO ALL WHO GAVE SUGGESTIONS.
JR.