Extremely weird problem whilst Downloading

This problem JUST started today... I don't think it's a Virus, I'm almost 99% sure it's not. But here's my problem.. It's really, really weird.

I don't have ANY performance problems at all, until I download something...

Basically, with IE or Firefox.. If I download more than let's say, 3 links. I start to lag really, really, bad. Like almost as if some hit enter on Crysis 78 times, and just let them all load.

So, I would close Firefox, and cancel all the downloads.. And everything would be fine.

But.. My sound would entirely stop working. If I'd check Device Manager, it would say everything is enabled and working, but there's just absolutely no sound..

So I have to reboot.

At first I thought it was flash because this also happened with videos on the internet.. whilst me download, so I uninstalled flash, and reinstalled the lastest version.. That didn't fix it. I ran CCleaner, it cleaned the Temp folder, etc.. That didn't fix it.

Does anyone have absolutely any CLUE what could be wrong?

PS - After there's no sound, if I restart.. Everything is back to normal again.

Edited by Oxymoron, 09 October 2009 - 11:25 PM.

Step One: Get rid of Vista.
Step Two: Get Ubuntu or a Mac.
--------------------------------------
OR, if you like Vista, try doing a repair install. Or run MalwareBytes Anti Malware. It sounds like you can at least run programs besides browsers normally.

What do you mean by DOWNLOAD - do you mean opening web pages or actually downloading a file ?