I took off my socket 775 fan for cleaning and to re apply thermal paste, it was abit of a hassle (i bent one of the pegs in the fan that had to be alligned into the motherboard, but after a struggle I got it in, but now when i turn on the computer i get nothing on the screen!! the cpu fan spins so i assume everythings ok their and i assume it cant be the cpu as i didnt actually tinker with it whatsoever I just reapplied the thermal paste on top of it, I have no idea what is wrong with it? Please please help me!

Have you checked all connections and made sure all components are seated correctly? Also is their any beeps or noises?

no beeps or noises and as far as i can tell everything is connected correctly

Have U Tryed taking out your graphics/3D card where the Cable for the screen connects try RESEATING the card and see if that helps what type of thermal paste did you use ?

not sure what you mean by reset the video card, but il take it out and leave it for like 6 minutes, and the thermal paste i used was silicone, ino its the worst kind but i i dont have much money atm

video card taken off /put back on, bios battery removed/ put back in. I am completly stumpted as to whats wrong with this.

Try resetting CMOS instead of just removing battery, there will be a jumper on the mobo, and you need to look at the manual to find it as well as instructions.