It won't work.
If the CPU fan is gone, it might be OK to open the case and direct a powerful fan at the CPU - however, this approach could compromise cooling elsewhere, so do not try it unless you know exactly what you're doing.
To answer your previous question: // do i need to repalce the PSU - OR the fan - OR do they come together //
The Power Supply Unit, PSU, comes as one unit with an integral fan. Although it might look as if the fan is replaceable, and it is physically possible to so so, do not attempt it - it could cost you your life - as I said before, PSUs have lethal voltages inside, even after they're switched off.
I would help if you posted the exact make and model of your PC - power supplies come in different capacities.