Windows 7 - Computer Lags 1-5 seconds trying to troubleshoot problem

Win 7 64
ASUS Crosshair V Formula
16GB Vengeance RAM
750 Watt PSU
NVIDIA GTX 570 Video Card
128GB SSD
Switched to 500GB 7200 RPM HD for troubleshooting purposes.

Hello all. I have tried a lot of things to figure out my lag problem. Randomly my computer will lag for 1-5 seconds, freezing in place then back to normal. During this time the HD light is on solid.

I have updated ALL motherboard drivers/bios/chipset/SATA etc., HD and SSD firmware up to date and video card drivers also. Run several virus scans with 5 different virus/maleware/spyware programs. I replaced my RAM and tried different hard drives. I have tried two different nvidia video cards with up to date drivers cleanly installed. I have reformatted both the SSD and HD (with up to date drivers installed) with no programs installed but Skyrim, Dark Ages of Camelot and my Anti Virus AVG Internet Security and also with and without AVG running. I have turned off and then back on the LPM for the hard drives. I have also turned off service indexing before I reformatted and left everything as default after reformatting

Currently after start-up I have under 50 processes running including system and user files. This happens while watching a movie, playing a game, surfing the internet or typing a document.

I am looking for anymore troubleshooting tips or solutions that can be offered.

Have you defragged? (Don't on the SSD). Which drive is your OS on? Have you scanned for with anything besides AVG? Is your computer overheating? How long have you had your hardware?

I have defragged. I have an OS on the SSD and the Disk Drive (SATA) right now I am experiencing it on both even if I have the SSD taken completely out.

The temps are: CPU 42C; GPU 37C; Disk 25C (SSD); HD 28C.

I scanned with AVG, Spybot, Malwarebytes, Adaware, Super AntiSpyware and Hitman Pro plus I completely wiped and reformatted both the SSD and the Disk Drive.

This is a fairly new gaming PC built in September 2011. The only older part is the CPU which I just ordered another one with an Arctic High Performance Heat-sink Fan for better cooling with a PSU that has more watts. I also blow out the PC regularly so there is no dust build up.

This would be a stock Windows 7 install, correct? Not modified / hacked in any way to remove components, services, etc. ala vLite or RT7Lite?

Yes stock windows 7 64 home premium, no hack at all of any kind.

I was reading other posts and tried the "How to Optimize Windows 7" on this forum but I am still experiencing the problem.

It's somewhat hard to say specifically what it is, but it can be a driver issue, antivirus, etc. What you can do, however (especially if it happens frequently) is download/run procmon, which will start a log, and then filter on disk activity and see what's actually being read or written to or from the disk at that time.