I just wanted to express a few thoughts about computer equipment. This is not a mac vs. pc kind of thing.
It's more of a warning stemming from personal experience where my personal pc was starting to get a bit bogged down after 4 years of neglect. It was slowing down and I was ignoring some of the little warnings. I'd just patiently restart the computer and keep on working.
Well, I now have a fancy 40GB external hardrive excised from the worn and tired wreck of my laptop. Worst of all though, was not having a comparable back up computer to work on and losing almost two weeks worth of productivity.
So, have your pc or mac serviced annually at minimum. Don't ignore the error messages and keep the lifeline to your business functioning properly.