I just installed Firefox (never had it before), and now WA just acts strangely. There is a bit of lag in the menu, and the task manager shows more than 90 % CPU usage.

I rarely play WA anyway, so the problem might be somewhere else, but I can say for a fact that I've never had such problems before.

Recently, I've been turning off the nsvcAppFlt.exe process from the task manager because it causes problems with my uTorrent. Maybe the fact that it is off affects WA?

Suggestions?

Uninstall Firefox temporarily and keep this AppFilt process on and try to run the game again. If the problem continues then you know that it's not caused by either of these.

nvidia application service filter? this is what i gather from the short name nsvcappfit.exe

so i reccomend finding what actually relates to that process and if it is your videocard drivers then yes, most likely stopping that does cause WA to go weird.

firefox 2.0.0.4 works fine, but im not sure about the firefox 3 alpha's.

nsvcAppFlt.exe:

"NVIDIA Network Access Manager is part of the NVIDIA Firewall used on certain Asus motherboards" ... (http://www.google.com/search?&rls=en&q=nsvcAppFlt.exe)

If it's related to your firewall then it will certainly affect WA and would explain the problems your having with uTorrent. Not being familiar with it at all tho, I'd suggest leaving it on and checking your portforward settings.

Firefox would never cause any problems like this.

Tip: Uninstall firefox. Install Opera.
www.opera.com

Tip: Uninstall firefox. Install Opera.
www.opera.com
Don't be fooled by the temptations of the dark side!

But the dark side is faster and uses less resources and is more standards-compliant, even though it doesn't have kitchen sinks or coffee makers.

Yay, fellow darkside minions... I bet almost all of the 1.6% (http://www.w3schools.com/browsers/browsers_stats.asp) is made up in this thread alone :P