My computer was dusty inside.  I had vacuumed as much as I could.  They blew the dust in the correct way, at first, from the inside of the CPU.  That was appropriate and I was fine with that work.  Then, I watched the guy, blow the heat sink where the fan is where most of the dust was.  That dust was not harming the computer at all.  I guess he decided to clean out the heat sink.  At first he started to do this appropriately by blowing it from the inside CPU to the outside.  He didn’t understand that it didn’t matter that the dust in the heat sink was there.  He started to blow from the outside to the CPU.  That killed my computer, it is completely dead.  I could not prove anything, so I just asked for my money back.  They did give me my money back that I paid them, minus $50.00.  This work was on an expensive Apple computer, I had paid $2500.00 just for the CPU.  I took my CPU to them and they did the cleaning in their parking.  Brian seemed to care more about their bigger clients.  He seemed clear that he did not care about my computer from the beginning.  He was unfriendly and uninterested.