A few days ago, I installed the Abacus F-14D for FS2004 (for God only knows what reason - the IRIS F-14A/B is amazing)
Before I started flight sim to test it out, I was instant messaging someone on Facebook (using the browser Google Chrome), and AVG Free did a restart (I accidentally hit "restart now" instead of "Postpone")
And the next time I started flight sim, not only was the game slow, but the entire program was running slow even in the create a flight, settings, and all those other tabs and options.
I uninstalled the F-14, but I'm still having no luck.