Try reformatting with a fresh image of windows, without any bloatware on it. You might have too many background tasks. But seriously consider an SSD, it will make a hell of an improvement EVEN if you have tons of bloatware.
A 120GB OCZ vertex 3 can be had for around $70 nowadays, hardly that large of an investment. Trust me, it's really worth it. Using it as a boot drive will make you wonder how you ever lived without one.
Waiting for my payment, will receive in a couple of days
Can't wait to buy one!