I replaced my cpu fan in my dell 780,and it runs at full speed,and I cannot stop the error message. I also have a problem with my usb keyboard,and mouse that does not work in my bios screen and I cannot make any changes to boot sequence, or any other settings so now its not booting properly either. so can you help me please. the fan i installed is an exact match for the original,and rewired it like the original,and it works. I am frustrated,and dell seems like little help.