Can't play videos anymore, games slowed down.....

I have a MAJOR problem!

For some reason, between yesterday and today, I can't play any video files any more. MPG, AVI, you name it. I start a video file, the PC slows down, the CPU usage goes to 100%, the video refuses to play, and I am forced to stop the video from starting with Task Manager. Only when I go into video properties/advanced/troubleshoot and slide the acceleration to NO Acceleration do the videos play. But, I can't play any games anymore at that setting.

I also noticed something else. I have Windows XP and Windows Media Center Edition 2005 in dual-boot. I boot into Windows MCE and my games run ALOT faster!!! The video files load up without a hitch! And the PC runs super smooth!

What happened to my XP install? Is my OS corrupted due to overclocking? I am going absolutely insane over this. I only use MCE as a secondary OS. So, I have all my stuff installed in XP. There MUST be a way to fix this! I don't know what the heck is going on!! :banghead

Full specs, please. OS corruption may have resulted if you OC'd too much and pushed PCI frequency too high (if unlocked), or some other problem.

Done any driver changes lately? Picked up any viruses or unmentionables?

AMD Athlon 64 3000+ OC'd to 2.4ghz.
1.5gb PC3200 RAM
ASRock 939 Dual Sata2 Motherboard (ULI chipset)
LOTS of hard drive space.
500w PSU
Windows XP Pro +sp2

The only driver changes were to the newest nVidia drivers. But I rolled them back and the same result.

I'm currently using my MCE install right now and that seems to be running smoothly. I hope it doesn't become corrupted as well.

Check video acceleration.

Videos only work when I slide the bar to "No Acceleration". Then, they play, but are slightly choppy.

I don't get it.

Why do games play so much better and faster on my Media Center version than my install of XP?

Why can't I use hardware acceleration for video playback anymore?

What happened to my XP install in less than 24 hours??

It sounds like you may have picked up something that severely hogs system resources. Checked for spyware and viruses?

Yep. I ran Spybot Search & Destroy. It just came up with some cookies.

I should probably do a complete scan with some other programs as well as a full virus scan with something other than F-Secure (which says the system is clean)

Yeah.

I had an odd case that resulted from a problem with perhipheral devices, namely a HP printer. It was broken, we left it plugged in, and it generated spurious signals, slowing us down drastically. Windows is weird.

Reload your chipset drivers and then reinstall your video drivers. See if it helps........it can't hurt.

When I first installed the Motherboard, I didn't reinstall the OS clean. I just let it go because it seemingly dealt with the change without a hitch.

Well, I guess I just met the hitch!

Lot of re-installing to do tomorrow.....