Windows 7 - I really need help, please.

Hi I been running windows 7 for 3 days and I'm already experimenting some problems. Is starting to get slow, real slow and on the CPU meter after opening any application it runs to 100%. it blinks(windows & the screen), My icons are disappearing, and when i try to put it back on sometimes it works sometimes it doesn't. The background I will set it to be changing and after a while it will just stop. In advance thank you.

CPU.............Intel Core 2 Duo E7400 @ 2.80Ghz
Memory........8GB
Hard Drive....372GB
Model...........Gateway GT3234m
Antivirus.......BitDefender 2010
(It was a clean instal)

Try totally uninstalling Bitdefender, see if it does anything. Could be a culprit.

thank you my friend, I'll try it right now.

by the way excuse my ignorance, but what is culprit?

• Main Entry: cul·prit
• Pronunciation: \ˈkəl-prət, -ˌprit\
• Function: noun
• Etymology: Anglo-French cul. (abbreviation of culpable guilty) + prest, prit ready (i.e., to prove it), from Latin praestus — more at presto
• Date: 1678

1 : one accused of or charged with a crime
2 : one guilty of a crime or a fault
3 : the source or cause of a problem

thank you.