"i've tried to put a new celeron 733 mhz processor in my pc,but i can't get the fan to work"
If it's plugged into the correct place, and you've tried another fan - then the only other thing likely is that the motherboard or PSU is faulty.
"When i turn the pc on, nothing happens,i can't even get into the bios"
Really nothing? - no light, fans etc? Try another PSU or motherboard. Check the front panel connections to the motherboard. Does it work if you put the old processor back in?