hi there.. i am facing some problems..

i am currently troubleshooting my computers..and seems LIKE the CPU fan it not working..can any ONE diagonse this problem....the PSU is working..then MB has power...thanks in advance..! Can the computer boot up?
When did this problem start?
Also, what are the full system specs? What kind of CPU is it? Different fans for different CPUs.

Along with Deerpark's QUESTION of whether or not the computer works properly:

CPU fans need to be connected to the motherboard for power. Check this connection. Has a large amount of dust accumulated on the fan? This can cause it to jam. With the power off, turn the CPU fan with your fingers and make sure it isn't stuck.

If it has power and doesn't appear to be jammed, it may have just died (it happens). Depending on the CPU, these are usually replaceable. (Some older CPUs like versions of the Pentium II had a built-on fan that couldn't be changed). If everything else is working just fine, purchase a new fan. LIMIT your use of the computer until you can replace it to avoid overheating.