A client comes in, carrying his SFF PC back in. He'd been earlier, insisting the PC had a problem. At that time, we tested it in front of him; everything tested fine and he left happy.
Flash forward to this afternoon. He'd called in, saying the PC wouldn't make it past POST. He was quick to tell us he'd worked in PC shops before, mainly on Macs. He felt he had his problem pegged. We brought it back to the bench, and after doing a quickie internal check [another tech had handled it this morning] we booted it.
What do I see? MemtestX86.
I ask him if the tech had checked the CD drive before he'd left earlier. Nope. I asked if he'd checked the drive SINCE he'd left the shop. Nope. When I popped our test cd out and rebooted, the PC booted normally.
My gripe? If you're going to present yourself as a tech, PLEASE make sure you've checked the obvious first. Find out where POST starts and ends, and RTFM....
I gotta admit, though, the look on his face was priceless.