Windows 7 - Problem with Windows 7

I Installed windows 7 today in my PC everything is working fine but a problem occurs when I shut down my pc.The screen shuts down but the smps and CPU fan keeps running. I have to shut it forcibly by switching off the power; no other way. I have a Core2duo E7400 2.8ghz processor and 160GB PATA HDD & 2GB DDR2 (800mhz) Ram installed my MB is Asus P5KPL-AM/PS. First I thought it was a bios problem.So I updated my Bios too but still the prob exist.
This problem does not take place in Windows Vista or even in XP only Windows 7.
Guys pls help.
I don't wanna install the old OS again......pls guys

How have you configured your "power options" ?

Will Windows 7 hibernate? If so, use it until you troubleshoot the Shut Down problem.

At Control Panel>Power Options, choose to make pressing Power Button shut down the computer.

Now press the Power Button and what happens?

There is an option in the BIOS for the fan to always run. I would uncheck that too.

It is possible that a program or device running in the background is not allowing your computer to fully shut down. To check if a program or device is interfering, follow these steps:

1. Open Performance Information and Tools by clicking the Start button , and then clicking Control Panel. In the search box, type Performance Information and Tools, and then, in the list of results, click Performance Information and Tools.
2. In the left pane, click Advanced tools.
3. In Advanced Tools, under Performance issues, click any issues that are listed.
4. Read the information in the dialog box that appears to learn which programs or drivers are causing problems.

Hope this helps!
Cassandra
MSFT Windows Outreach

While in Advanced Tools, check the Performace log listed there to see what errors might be occuring at time you are attempting shutdown. Repeat errors will increase certainty what is causing problem. Update or reinstall driver/application.

Also while in Advanced Tools, Generate a System Health Report

Hey I tried it out there was this Graphics driver problem I updated the driver too but still the problem xists but how do I solve it the only thing i did is changed the power button to hibernate and put it to hibernate. One more thing that i would like to add is that the Hibernate option do not come in the shut down list as it normally does.

I had recently installed the Windows 7 in my PC. I haven't changed anything

It use to work absolutely fine wid XP the problem started wid 7 only

then you should configure your power scheme