Sometimes Power Supply is sometimes overlooked when buying a new PC, and may cause headaches later in your PC computing.To give you and example, a year ago I encountered a problem that seems to point to a non-power supply related, but it turns out to be a power supply problem.
Here's the situation:
A customer calls me and complained that his unit is not booting, so I went to his place and troubleshoot the unit,the first thing I did was turn off the PC, resocket the IDE cable and re-test the unit, upon testing everything works fine, so I tell him that maybe its just a matter of loose connection.
The next day he calls me again and said that the problem re-occur, so I went back again and check the unit all over again, I resocket the IDE connector again and re-test the unit, this time the hard drive is detected intermittently, so I suspect that its a harddisk problem.I even tell the customer that maybe your harddrive is ailing already.
I went to troubleshoot further, one thing I noticed during the troubleshooting process is that, there are times that the CPU unit, black's-out once in a while when harddrive is connected,but if you don't connect the harddrive, everything's fine.
Its really a very confusing problem, you can mistakingly point to a defective harddrive.Luckily I have one spare harddrive with me, so I install it on his unit,but problem still exist.
With that I now started to suspect the PS unit, so I disassemble it and check its internal components, and I found out that there are lots of bulging filter capacitors in its circuitry, which convince me that its the one that's causing the whole thing.
I tell the customer that it must be the PS unit that's causing the problem and it should be replaced.After replacing the PS unit, everythings works fine.By the way, the PS unit he is using is the generic one's(normally bundled on a new PC casing).
Generic PS unit are a little cheaper that the branded one's but if you compare its performance its difinetely worth the extra bucks you add in purchasing a branded PS unit.