I was able to play DMC4 on my pc without any issues, but after I had to reformat and reinstall windows xp (long story), the game is not even playable. After I reinstalled the game, I noticed that the sfx in the main menu would lag (ex. female voice trying to say the name of the game, but said "devil devil devil may cry", and hearing multiple clicks from moving my cursor to select an option when I only moved it once). I overlooked the issue and started a new game, only to find that the same problems were happening in the introduction cinemetc, such as the soundtrack stuttering while the video was still in motion, or vice versa. Then I started playing the first level, but both the video and sfx were lagging during gameplay, making it unplayable. Any ideas as to what is going on?

System Specs:
AMD Athlon 64 X2 5200+ 2.70 GHz
4 GB of RAM
Nvidia 9600 GT 512MB PCI-E video card
Windows XP Pro

Video Game Consoles & Games - Capcom - Devil May Cry 4