Computer in oil inside refrigerator
While what you do could successfully transfer heat from your PC, have you realised it will only be transferring it to your room. With the addition of a fridge, your room will actually end up hotter than it would be without this computer cooling - it may not even be quieter, as the compressor on a fridge can be quite noisy.

If you do decide to cool your PC, there are very cheap cooling systems which will be much cheaper than buying a fridge and building your oil setup, but all will leave you with more heat than you started with in your room, as no system is 100% efficient.
Check out sites like overclockers.com, as they seem to have a good handle on cooling computers.

I would suggest instead, fitting air conditioning to your window if you really do want a cooler room. That way you are moving the heat outside.