New Build Cpu Fan Spins Down

I need any and all suggestions on what could be causing this problem in case its hardware so I can send it back.

Just got my friends parts in, dfi sli bridge lan party mobo, amd64 3200. leadtech 6600, mushkin ddr2 3200 (black sticks). and a rosewill 500w power supply (the one w/2 fans)

Anyway we put it all together, pushed the power and everything lights up and works but the cpu fan spins up and goes for a second at full speed but then spins down and stops--i then have just shut the whole thing off so I dont know if it'll even boot yet.

1.First clues, the styrofoam on the heatsinc side of the packaging was busted up a little and some of it got onto the thermal paste, I just blew it off. later today i am going to hopefully get some more from a friend and reapply to see if its an overheat issue-btw whats the best way to clean the old stuff.

2. 2nd option: Board shorting out somewhere. havent undone it yet to see if its touching more than the mounts but i guess ill try it after #1

3. cables. rechecked all power connections. havent tried a different psu. think an old 300w could at least boot the system up? Probably but just want a double check on that so i dont waste my time.

4. Dont know thats why im posting.

Any and all opinions are welcome. doing this later tongith (us mountain standard). thanks ahead of time.
destructo

 

Have you reset the cmos?Have you plugged in the 4 pin ATX into the mobo?The 300w wont boot it up if it hasn't got the 4 pin ATX plug.

 

Havent reset the cmos, its right out of box so I didnt think of that, havent checked the 300 w but its the only one i have around. and yes all 3 plugs are in. (maybe its 4, not home right now but not the point, double checked that one already last night)

Anything else?

 

So its only the cpu fan that stops all the others spin,inc HD

 

Reseat the ram,just use one stick to start off with.

 

Dont think Ive gotten far enough into it for the harddrive to spin up. Just saw the cpu fan shut down and so i flipped the system off immediatly each time. Wasnt sure at the time how long I could let it run w/out fan. My buddy said I should at least let it try to boot. Probably do that when I get home as well.

Everything else shows somesort of operation as far as I can remember right now