Help needed from the good people of Toms Hardware!

I have a problem with my home build, and yes I have read the " READ before posting about boot problems!" thread.
so, I pu together the computer without any problems and connected to the monitor, everything fired up but no bios loaded, I went through afew steps in the above thread but now I'm in a worse position, when I turn it on the fans go for a second and then turn off over and over, if I plug out the 4pin connector over the processor it all fires up okay. So any ideas on what needs to be done?
All help welcome, I have a feeling its somthing to do with the thermal paste but I dont know...

Its my first buil by the way. Thanks!