A fan went out on a CPU cooler the other day. Got tired of seeing it sitting there and not running but I didn't have a 90mm fan to replace it with. So, I found a 120mm fan and zip tied it to the heat sink. Looks like poo but he CPU is running cooler now that it ever did. The moral of the story is that if things didn't break, you'd never have the chance to improve them when you upgrade. Just make sure the new PSU is oversized (way more watts than needed) for a longer life and an 80+ gold or silver rated unit to keep the electric costs down.