hmm, lol skunk... I think that SpeedStep guide may be a bit much for the OP to digest right now?
The short explanation is this: cpu speed = system clock x cpu multiplier. SpeedStep takes your regular multiplier and divides it by 1/3 to conserve energy. This is all useless mumbo-jumbo right now I know, but it will help you gain some idea about what's going on and how to overcome it.
My idea was to stop your system from using SpeedStep. Stopping SpeedStep only requires that you do something, anything, that uses your cpu. The more intense the application, the better your chances are that you'll disable SpeedStep.
Microsoft Minefield or Hearts are not good choices because they do not require a lot of cpu activity. Games are not a good idea for my suggestion, because then you won't see your installer... so try what I said and go play a video you have on your machine or stream one from youtube if you don't have any.
If you don't want to mess around with the bios, I have an idea that might help? Put your game cd in the drive and let the installer prompt appear, but don't click install yet. Then open a browser and go stream some video... do anything taxing that will allow SpeedStep to return your machine to it's normal 2.2GHz speed. Once you've run the video for a second or two you should be fine, then click on install.