It's always a stressful thing to contemplate, but Ben convinced me that his old desktop (which he never uses since he migrated to a small, very powerful laptop) is a better computer than my main development machine, which has been loyally running daily for about 4 years.
More memory, faster processor, better video, etc. I haven't had any problems with my current, very reliable Dell, but moving to a freshly-rebuilt, totally clean PC is too good to pass up.
There were some hurdles to eliminating the few issues with his machine, to wit:
1) It had a very noisy fan, but Ben found a free utility called SpeedFan, that monitors CPU heat and adjusts the fan level accordingly. Most of the time, it's now a whisper, occasionally rising to the level of a murmer.
2) The PC would not wake from Hibernation. I use Hibernate all the time, so this was a problem. He updated drivers on all peripherals and finally ended up flashing the BIOS on the motherboard - problem solved!
3) The built-in Ethernet port was flaky (i.e. not working). Ben said that the guy he bought the unit from admitted this from the start, so he's been using a USB WiFi connector with it. Yesterday, I made a pilgrimage to FreeGeek, and bought a PCI Ethernet card for $5. I popped it in the morning, plugged it directly into my router, and, voila, I am in business.
Now comes the onerous task of moving all my files and applications over, but I just might take the next big step (I've already installed and tested my super-critical apps), to unplug my old computer, plug in the new one, and, little by little, get all my files and apps moved over.
It's a little scary.