Cpu fan full speed?

[mathiasd.hauge]

First my specs:
Asus p5b plus
4gb ram 4*1GB 800mhz
E8400
280w psu
Nvs 290
250GB hdd

When i boot my pc, the cpu fan go full speed (or very fast). It also gets stuck on BIOS Flash screen. So I can’t get into windows. The only way I get into bios is by removing and replacing the cmos battery. In the bios i can see that the cpu fan is on 3500-3700 rpm. It is on the optimal setting. I changed it to performance mode and saved. The fan were much quiter! So i boot my pc again and boom, its stuck on bios Flash screen. I cant press anything. So i try to remove and replace the cmos battery again. It boots fine but now the cpu fan is on full speed again.

Anyone know how i get into Windows and my cpu fan will still be quiet?

 

[NightHawkRMX]

What do you mean it boots fine? Later you said u needed help getting into windows. Does it boot or not? What are your thermals looking like?

 

[mathiasd.hauge]

It always boots, but if i dont remove the cmos battery, it gets stuck on the bios screen where you press Del or f1 etc.

 

[mathiasd.hauge]

My cpu is 40 degrees in bios.

 

[NightHawkRMX]

Try to get into safe mode.