Ok, if it is slow "at the flag" then it is what it is loading upon start up.
Run "msconfig" and check what programs are loading at start up.
You can uncheck things you don't need or want, but be careful. Somethings you won't recognize, but are needed to run the OS. Leave anything from Microsoft.
You might also look into a "Windows 7 Optimization Guide," such as here.
The problem I've seen is that all the new software you install thinks that it is the most importent thing you have, and set themselves up to "run at boot," or very similar. Many, if not all, are not neccessary. They will run fine when YOU choose them to run.