The biggest disadvantage to building your own desktop is that when things go wrong, you actually have to figure out what it is. A couple weeks ago, in the middle of a game, my desktop shut itself off. It would no longer get so far as POSTing, and sometimes the power supply wouldn’t do anything when I hit the power button. After some fiddling, I determined that it was most likely the motherboard, and since I had a three-year warranty, I sent it back to MSI for repairs.
When a different motherboard (of the same model) came back, it still wasn’t working. This narrowed it down to the (cheap) power supply or the (less cheap) processor. I randomly came across a great rebate deal on a 350W power supply at CompUSA, so I ran there and purchased it. I was lucky, and that did it. It only cost me ten dollars in the end, and my computer now seems quieter, too.
I only wish it hadn’t taken a month.