(Typing from Safe Mode)
Asus G73Jh laptop
Windows 7 64-bit Home Premium SP1
ATI Mobility Radeon™ HD 5800
Intel Core i7 Q720 1.60GHz
8 GB RAM
1TB hard drive, pre-partitioned into 3 segments, 2 of those with about 30% free and one nearly full (not the one with the Windows, etc. files.)
In a nutshell: my machine only operates normally for 2-3 minutes before things rapidly slow down, eventually to the point of unusability. Even then, my CPU usage is only 1% and memory usage ~20%, mostly from the open IE window.
Here's what happened, and it makes no sense: I usually shut off my comp at night, so my scheduled 4am deep virus scan, from my Viper anti-virus, doesn't happen. (I've had the program for a year now and have been very satisfied.) One night I left my computer on, and in the morning discovered that the scan had apparently frozen midway, and although my system wasn't technically "frozen," it was unusably slow. I was forced to shut down the computer by holding the power button.
A week later, (yesterday,) I decide to try a deep virus scan again. I bring up a full screen game to pass the time. After a couple hours, I notice my game is running slow and that my machine is a bit warm. I exit and find that Viper is attempting to update itself midway through the scan, even though I already saw it update when I first opened it. My entire machine was terribly slow, so for all intents and purposes I couldn't open or do anything else. After a few minutes of no improvement, I again had to shut down my computer by holding the power button. (Note, that's something I almost never have to do. It's a very well-behaved computer usually.)
When I restarted, I was presented with the problem I currently have: after a couple of minutes, everything suddenly takes 20-30 seconds to open or perform an action. Soon things essentially freeze unless you are very careful, only open one window and take it slow, although even then things turn south eventually. The end stage is when things are officially Not Responding and, after 10-15 minutes of being in that state, shut themselves down.
According to Task Manager, no program is eating up all the memory or CPU. As I said, it reports only 1% CPU usage and ~20% memory usage, mostly by IE. I was able to Google all the exe's in the Task Manager and everything SEEMS to belong. In safe mode I ran a normal (not deep) scan with Viper which turned up nothing but some standard cookies. I installed AVG Free and Malwarebytes Free and ran them both, deep scan, in safe mode, and they both turned up exactly zero problems.
I used a recovery point to restore my system to a point several hours before I attempted the scan-of-doom and the problem did not go away. I ran a CHKDSK myself and nothing seemed amiss.
If it helps, my computer seems unusually warm just running in safe mode, although not alarmingly so, and the fan always seems to be running at max even when the temp seems fine to me.
I'm totally stumped and would rather not send my machine away to Best Buy for a month, I'd really really appreciate any help or suggestions.