Windows 2000/XP: Click on Start-Settings-Control Panel, (or Start-Control Panel in XP), then double click on the "Networks and Dial Up Connections" icon, then find your type of connection type being used currently, either "Local Area Network" or "Dial-Up", then RIGHT click on it, choose "Properties". You should then be able to see the network components that are installed on the computer. If "File and Printer Sharing for Microsoft networks" is listed, click once on it to highlight it, then click on the "remove" button.
If you are on a LAN and file sharing is required,(on Win95/98/ME computers) then double click on "My Computer" RIGHT click on the C drive, choose "Sharing" from the menu and type a password in the password lines. Click on Apply, then OK, etc. On Win2000/XP machines you will need to establish specific "permissions" for each shared drive/folder. Don't share the entire C drive, and by all means, don't allow "Full" permissions.
_________________
In addition, please run the free online scan from the link below, then download "The Cleaner" which is a free trojan scanner.
Panda Antivirus Online Scanner
"The Cleaner"
http://www.moosoft.com

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic