Computer stopped working with a no input signal message. The fans in the computer case ran. Replaced motheboard and installed new video card. The new video card fan does not come on. Tried the old video card and the fan came on. Exchanged the new card for another and the fan on the card does not come on. Could two new video cards not work? Read somewhere that a psu could run fans but still need to be replaced. However, why would the old cards fan run? Also, the old cards fan is loose and needed to be replaced. When the computer stopped working there was a burning smell. The new motherboard has a 4pin connector for the 12v power, the old motherboard has 8pins. The current psu has 8pins that can be separated into 4pins each. Hooked up the motherboard with 4 pins. Is this ok? Any suggestions? Thanks for any help.