webroot was eating up too many resources of my PC. Also I use Kerio as firewall:
I had the same problem with webroot but it went away. Who knows.
Kerio is awesome. I was using ZONEALARM but it would it would eat up the processor at certain intervals. The web site forum mentions this problem but the replies from the company make it look like it's a user error. Then again ZoneAlarm is free and workable and it's more easy to use than the others.
Also:
Windows Updates: http://update.microsoft.com/microsoftupdate/v6/default.aspx?ln=en-us
And make sure you have SP2 installed: http://www.microsoft.com/windowsxp/sp2/default.mspx