IE and Firefox work independently. IE setting cannot effect Firefox. There is a setting in Firefox that will clear your personal data every time you log off. Check you Firefox options menu. Click Tools>Pivacy. You will see the box there that may be checked to clear you data every time you log off.
As for the weird things that are happening. Torrents are a source that may infect your machine. I would run a couple of scans to be sure your computer is clean.
Update and run your Anti-Virus program. Don't have one? You can run a free online scan from CA.
http://www3.ca.com/securityadvisor/virus...
Run Spybot and Adaware weekly.
Download, update and run Spybot---http://www.safer-networking.org/...... . Don't forget to use the Immunize feature.
Download, update and run---http://www.snapfiles.com/get/SuperAntiSpyware.html
Now to prevent spyware from being installed in the first place....
Download SpywareBlaster---http://majorgeeks.com/download2859.html...
SpywareBlaster doesn't scan and clean for spyware - it prevents it from ever being installed.
It's main features include:
- Prevent the installation of ActiveX-based spyware, adware, browser hijackers, dialers, and other potentially unwanted pests.
- Block spyware/tracking cookies in Internet Explorer and Mozilla/Firefox.
- Restrict the actions of potentially dangerous sites in Internet Explorer.