HOW CAN I KNOW THAT CPU IS 32 BIT OR 64 BIT?

Well, I tend to disagree with most answers so far. A processor has to be 64bit capable to address more than 4GB of memory. Current i-series processors are 64 bit. Go back to the C2D processors, and not all of them are 64bit capable. Find your processor model number, go to google and find out what architecture it uses - 32 or 64 bit. If it is 64bit, stick to win 7 64bit for best performance. Older games etc can be run in compatibility mode if you have problems in 64-bit mode.

CPU Is Not 32 or 64, As the guy above me said. It's your Operating System that is 32 or 64. You go into "My Computer" Or "Computer" then you click System properties. That location contains your computer specs.

just right click on your desktop and choose "properties". From there choose the "settings" option & u'll see the """color quality """"............. simple isn't it???

right click in desctop and then property.

WINDOWS 7 IS AN OS, NOT A CPU. right click on "computer" and choose "properties" you'll see. and yes, you can change your windows from 64 to 32 bit. But you'll need to fully re-install your windows 7. Which means...you'll need to buy a 32-bit version of windows 7.