Vista - No Video on WMP

Due to my virus scan saying it was a threat I ended up deleting a file in my Config.Msi folder,now I noticed I cant play videos anymore. Since you cant download or uninstall windows media player on vista I don't know that to do. I tried System Restore but it always has an error and never works and I have the OEM version of Vista since I had my computer built for me and im not sure if it will allow a repair. Any ideas?

If there is no way to repair windows media player with the OEM anyway I can get a disk from Microsoft which allows me to do the repair? Or is there anyway I can recover things I deleted from the recycling bin? The problem doesn't just end with windows media player I cant watch videos from my Nero program as well.

Dtruth-
Hi, my name’s Cody, and I’m working with the Windows Media Outreach Team to help answer questions folks might have. I’m definitely no technical expert, but hopefully I can at least help you get you pointed towards the resources you’ll need to solve your problem. I’m not sure why a file in the config.msi folder (which I think is reserved for storing temporary files used in installations) would mess with your video playback, but let’s see if we can figure it out.
When you try to play the files in Windows Media Player, do you receive any kind of error message? Or do things simply not play? What kinds of files are you specifically trying to play (.avi, .wmv, etc) that cause the problems? Let me know, and we can try a few things to resolve the issue!
Thanks,
Cody
Windows Media Outreach Team