Okay. The way I see it, I have three options so solve my PC heat problem: a) live with it; b) buy a 3Ghz Northwood CPU (that is, if I can find one); c) purchase a TAC (Thermally Enhanced Chassis) compliant case. Option A is a non-starter, B and C will cost me money. I think option C is the way to go, though.
I must admit, my current case isn't exactly spacious, the airflow is pretty much non-existent as far as I can tell, and I am convinced that it is the failure to get rid of the warm air from around the CPU that is causing the overheating. Hopefully, if I can find a decent enough case, all my heat problems will be solved.