How can I tell how fast my pc is?

http.www.belarc.com
download belarc advisor.
it will give you all info pertaining to your pc...

It really depends on how old your computer is. But if your computer is running Windows XP and is less than 5 years old, try this:

- Right-click the My Computer icon on your desktop
- On the General tab, under "Computer:" it should tell you the type and speed of your processor.

Also on XP, you can go to Start | Run, type "msinfo32" without the quotes and look at the System Summary. It should tell you in MHz how fast your system is (i.e. ...GenuineIntel ~3391 MHz means you have a 3.39 GHz Pentium Processor).

If you go to start, then right click the mycomputer icon, go to properties, it will bring up a screen giving you information about your computer, including speed.