There are several ways to find the actual speed of your computer.
The easiest way is probably for you to observe the bios/cmos screen, which is usually the first screen (black screen) that pops up when you start your computer up. It could tell you what type of processor and what speed you are running.
Second, you could get third-party programs that tell you. Some of these programs include Sisoft Sandra, WCPUID, 3DMark2000, 3DMark2001SE, 3DMark2003, or many other programs that will tell you.
Another way, which I do not recommend unless you know what you are doing, is to actually enter your bios and look at your FSB (Front Side Bus) speed and multiplier settings, and do the math (FSB speed X multiplier setting). However, this is probably the most dangerous way to check your speed, as you could inadvertently change system settings that could crash your computer.
<font color=blue> Ok, so you have to put your "2 cents" in, but its value is only "A penny's worth". Who gets that extra penny? </font color=blue>