The one we have at my office was purchsed immediately after they came out. At the time of purchase I upgraded to 1gb of ram. It's been running quite nicely all this time. I work for a newspaper and some of our machinery runs solely on classic applications, and occassionally things will malfunction and I have to reinstall classic. And about six months ago, it started shutting itself down multiple times per day. The fans would start raging and the machine would either shut down or go to sleep with no warning. This problem was solved by opening the tower and blowing the dust out of the fans and off of the heatsink. The heatsink was actually so caked in dust you couldn't even see it. Other than those issues, it has been a very reliable machine..being used between 12 and 16 hours per day since we bought it.
yea hopefully u used compressed air
and that will happen with towers