unwanted characters seen on the screen

Hi,

I recently re-installed WinXP home edition using the Recovery CDs. I
had also installed
a few gaming softwares. After a few days of the installation, strangely
"\" characters are
getting typed on the screen without my intervention. I have Norton
Anitvirus software
along with the latest virus definition files. Even a Full Scan of the
harddisk did not reveal
any virus.. Any suggestions would be appreciated...

regards
Sujai