Sluggish performance, windows 7 home premium 64-bit

I just did a clean install of this system three days ago and its alot more slower than my previous Q6600 setup ever was. The cpu core temperatures are fine, however there is a very noticable system performance loss from the build that I used to run.

Flash video playback and just general system usage is slow. There is noticable pauses scrolling in IE9, slow picture loading, opening media player can take up to 30 seconds, and even a delay when I right click to do something. My old build, an EVGA 680i and Q6600 G0 never had this problem.

I have the following system build
i5 2500K
Gigabyte Z68A-D3H-B3 (F11 Bios) - Revision 1.3
4 GB Gskill Ripjaws
Geforce GTX 260 216 896MB
Seagate 3500418AS 7200.12 barracuda (Flashed to firmware CC49) - Connected to Sata3 port 1

I already did one fresh install, but maybe I messed up the proceedure. The system has been slow ever since it first came online even without anything installed.
So I am going to try one more clean install.

I just need to know what the recommended method is.
When I read the intel website for chipset install it said to first install windows, update everything thru windows update first and then finally install your drivers.

When I look at online guides, they say to install windows and then immediately install your drivers. Chipset first and additional drivers next.

Please tell me which method is best, because I have been trying to fix this problem for 3 days now and I feel my only chance is to reinstall, but I need to do it the right way.

That's a tough one. FWIW - I would remove the GTX 260 & use the onboard chipset graphics, just to see if there is some conflict causing the sluggishness. Hopefully, you carefully reviewed all info on setting up your new mobo & installing any drivers/utilities that came with it.

Every week we have multiple users who don't understand why their clean install performance is screwy until we learn they changed out all of their drivers using old XPired methods which ignore the fact that MS spent a fortune creating the first driver-complete OS in Windows 7.

Do not change out drivers given by the installer and updated quickly by optional Windows Updates unless performance quality dictates doing so. Any drivers missing in Device Manager afterwards can be imported from the Support Downloads webpage for the computer or device model.

In your case I would clean reinstall following these steps based on thousands of successful installs we've helped with here: Reinstalling Windows 7