Happy married Vista too slow with movies

I have installed Window Vista on my dual core PC since day two. I am pretty happy with it since I never have to restore my partition using Ghost, something I been doing with my laptop running XP for more than 20 times due to virus. The performance is a bit slower than running XP but I am happy because I manage to remove all the .dll causing Adobe Premiere to crash using a debugging tool. God this China Story blog is turning into a tech blog. Anyway I try playing an UFC Ultimate Fighter 6 final .avi video file downloaded from the internet and it is so slow. The sound is ok but the screen is play at 10 fps. I play the same file on my single core laptop running XP and it is very fast… So I figure it can be virus. Sure enough I ran a spy ware software and found a KGB_Spy spy ware which has been key logging and remotely stealing information from my PC. After I check that no illegal credit card payment was made in the last 30 days I try to play the UFC file again but still the same thing, it is very slow. But when I play another older UFC file it is ok. So certain files are slow and certain files aren’t. So I run google search and find out from that Vista has content protection software that can slow down the PC. You can read all about it here.
http://windowsvistablog.com/blogs/windowsvista/archive/2007/01/20/windows-vista-content-protection-twenty-questions-and-answers.aspx

At least that’s what I think it is.

I also have problem playing youtube full screen on my 1680×1050. The sound starts cracking but is ok with normal size. I notice the CPU is ok 100%. But then it could be a flash problem.