w7 unusable after install

PROBLEM SOLVED

but dont know how I did it

After running memtest86+ 8 times with no erros I swapped the places of RAM-sticks.
Then I ran memtest86+ 4 times with no errors.
After that I clean installed w7 exactly like many times before and... BOOM, it works as fast as it should.

WTF was the problem? Id like to know that because now Im scared that my OS might start lagging again without any reason.

Anyways I updated pretty much everything including w7 and all the drivers and everything runs smooth, so lets say problem solved.



Thank you very much for help, +reps for you greg and BFK!

I also learned lots of stuff that I can use later-on if I need to, and I found out these forums are great. I will be using the advice that is given here if I got problems in future.

Did you check performance after swapping sticks?

Then you would know if it was that and not the clean reinstall.

Some suggestions:

Install programs slowly over time to gauge performance changes. Don't let any write themselves into msconfig>Startup as they become full-time freeloaders on your RAM/CPU and can spy on you. I only allow AV and gadgets/stikynotes.

Use a lightweight free AV like MS Security Essentials with the Windows Firewall.

Google repeat errors in Event Viewer>Admin view to see how others have solved them. Check also Performance log on Advanced Tools page accessed by clicking WEI score at Computer>Properties; look for issues cued at top of Tools page, Generate a System Health Report.

Save a Win7 backup image externally so you never have to reinstall again, just reimage to HD or replacement in 15 minutes.