BleepingComputer.com: Computer Froze During the night, been having lots of skipping and slowness problems

I woke up this morning to my computer frozen. It's been acting a little weird lately, and I'm not sure what to do. It was randomly powering off at some times, and wouldn't turn back on for a couple of seconds. All my temperatures are normal, I think. The problems seem to have been starting just after getting a new graphics card in august? Like I got the graphics card, maybe a month later, boom. Games start lagging as if I had network lag/high ping, but my ping is normal. Sometimes stuff'll take an abnormally long time to run. Alot of times I can't install stuff like zune/.NET Framework because I get a "Installation already in progress" error. I'm not sure how much of this stuff is related but it all started happening basically after I installed the Graphics card.
I'm definitely not the most thoughtful computer owner, I leave it on for long periods at a time, which I'm not going to do starting now. I'm gonna try dusting out the inside of the computer later today when I get off work.
I'd take actions to fix this but I haven't the slightest clue how to diagnose what's wrong. Can anyone help me get on the right track?

and now like...it wasn't loading half the stuff on my desktop when I had another window open...and now it's taking forever for me to move stuff OFF the desktop. It's just kinda stuck at "Discovering Items". And the firefox window is freezing pretty heavily too.
AND when I open a folder with a bunch of pictures etc. it's taking a considerable amount of time to even load everything in it.

This post has been edited by Dj Moltar: 30 December 2011 - 08:54 AM

System manufacturer and model?

How does the system run minus the card you installed?

Louis

If possible, before you take the card out, run the pc in Safe Mode and tell us how it runs then too.