im  having

 Windows 7 64 bit prof.

 2 GB DDR3 of RAM.

320 GB HDD

 2.80 Ghz

 core2duo

Windows 7 Is Slow

1. If the computer only has 1GB or 2GB of RAM try adding more RAM.
2. Make sure your drivers are up to date.

http://windows.microsoft.com/en-us/windows7/Update-a-driver-for-hardware-that-isnt-working-properly

3. Defragment Your Windows 7 Computer:

http://windows.microsoft.com/en-US/windows7/Improve-performance-by-defragmenting-your-hard-disk

4. Reduce Start Up Programs:

A. Click Start, type MSCONFIG in the search box, and then press Enter.

B. On the General tab, click Selective Startup.

C. Next change tabs by clicking the Startup tab.

D. Uncheck the programs you don't want to start when your computer boots (do not uncheck your antivirus program).

E. Click OK, then restart the computer.

5. Disable Some Visual Effects in Windows 7

There are many visual effects that can be safely disabled to speed up Windows 7.

A. Click Start, right click on "Computer" and select "Properties."

B. Click on "Advanced System Settings" from the left pane to open up the "System Properties" window.

C. Select the "Advanced" tab from it. Then Under "Performance" click "Settings."

D. Now uncheck any of the options you don't want to use (some options will disable Aero).

E. Restart the computer.

6. Open the Performance Troubleshooter

A. Open the Performance Troubleshooter by clicking the Start button.

B. In the search box, type "troubleshooter," and then click Troubleshooting.

C. Under System and Security, click Check for performance issues.

Optimize Windows 7 For Better Performance

http://windows.microsoft.com/en-US/windows7/Optimize-Windows-7-for-better-performance

Slow PC? Optimize your computer for peak performance:

http://www.microsoft.com/athome/setup/optimize.aspx