Windows 7 64bit is slow, can't find problem

[FofR]

I'm running Windows 7 Professional 64-bit. It was running fast a year ago. About half a year ago it slowed down dramatically during boot and the follow 10 minutes. I can't figure out why. I've done the following to no avail:
1) ran antivirus (Security Essentials) and antimalware (Malwarebytes) programs (no problems found)
2) cleaned up unused files and defragmented HDD (no noticeable change)
3) did a clean boot (still had the issue)
4) formatted HDD and reinstalled Windows... twice (issue still present from beginning both times)
5) replaced HDD, SATA cables, and RAM (issue still present)
6) utilized all the troubleshooter programs built in Windows (no problems found)
7) ran a CPU scan (passed)
8) Reset BIOS (no change)
9) Updated BIOS directly from ASRock (no change)
10) Ran Disk Check (no change)

Interestingly, I have another HDD in which I put the Windows 10 Tech Preview on. It runs perfectly. That same HDD was previously in my system with Windows 7 on it and the problems were still present.

Other info:
Processor: Intel Core i7 3770
Motherboard: ASRock Z75 Pro3
RAM: 4 x 4GB DDR3 1600MHz (default set at 799.9MHz)
Graphics: GeForce GTX 660 Ti

Any help to get my computer running fast again is greatly appreciated.

 

[PlatypusKnight]

Hi FofR

Welcome to 7 forums.
You did a pretty good job troubleshooting on your own.
Have you checked your RAM? . . .Ahh yes I just noticed that in your post.

Does the problem persist in Safe mode?

 

[FofR]

Yes it does.

 

[PlatypusKnight]

Would you be averse to a clean win 7 install?


I'm sorry I forgot that you said in the OP that you've already done that.

I had an idea when I first started thinking about your problem.

What do you use for a firewall?

 

[FofR]

I use Windows Firewall.

 

[Xmas]

Id try control panel/system & security/performance information and Tools/advanced tools/

and look at performance and resource monitor data

but check your virtual memiory size is set to 'windows recommended' value first

I spend a lot of time moving files off C drive to backup media, and defragiing, large/fast ready boost chip but still a slug, but it would 'stop' otherwise...

It is not unknown that things get slower after a windows update occurs