When I am logged into gmail, Firefox (3.6.3) is running constantly in background fluctuating moment to moment from 0-90% CPU usage (mostly 40-90% usage), but when I logout of gmail, this immediately ends - why and how can I fix this?
This started ~2 months ago. I have run anti-virus / anti-malware, but the problem persists. I also deleted all cookies. My computer has Windows XP with service pack 2.