CPU reaches 100% with nothing running in clean win7 install

For several months I have tried to determine the sluggishness of my cpu after a clean win7 64 install. Here is some background:

SPECS:
Core 2 Quad Q6700 @ 2.66GHZ
Intel DG35EC
Corsair 4X2GB DDR2
Hitachi 1TB | WD Ext 1TB
Geforce 9600 GSO 768MB
NZXT HALE82 650W
Win7 Home Prem 64 | Vista Business 32

This win7 home prem sp1 64 OEM was previously working fine for over 6 months then things went weird. By weird I mean that a normal boot would take several minutes to reach the desktop. Booting in safe mode did not change the length of time either. Another thing that occurred was my desktop background went black. I read somewhere that suggested I create a new desktop profile and this would fix things. I did not. I cannot be certain of the cause of this but I recall two events that may be related.

(1) I had a laptop die around this time so I was going to transfer its hdd contents to the desktop. I connected it via SATA to my MOBO. However upon bootup win7 did not recognize it. Could this have corrupted something? I ran SuperMalwareBytes but it turned up nothing.
(2) I windows update occurred around this time. With my MOBO and CPU being outdated is it possible that they are not compatible up to a certain update? I currently am running Vista 32 on the other partition with no problems.

I decided to reinstall win7 on the partition however this did not solve the problem either. The new install was still sluggish and at time almost unresponsive e.g. the cpu would be at 65% and higher just running Firefox while my 8GB of ram read <40%.

I then decided to reformat the partition first and then install it. Again this did very little. I currently have that one installed and have installed of the win updates since. I ran memtest86 and passed. I installed process explorer but could not identify a specific area that had an abnormal consumption rate.

Any advice would be great. Thanks!