just suck it in & take it in :)

OK well I reread all the posts - and sorry for missing stuff (suggest if you decide you want to tinker & want suggestions, you start new thread with full details of components and history and reasoning thus far )

But since this is not your computer or your money and you say you dont want to risk turning it on again, I suspect you would do better not to spend money on a PSU on the off chance, but take the box straight to the compUSA people, presuming they were the retailers. They will tell you if its the PSU as they have plenty of spares and test facilities and insurance. This would also reduce risk of data loss if you stress the issue to them and will bring about the swiftest resolution. (Is there a warranty ?)

PS I have also had to sort out my Dad's comp and it can be a difficult responsibility !! Luckily I had a box identical to it so I learned about the system when a virus trashed my C: drive :/ . So I was able to fix it np but he gets pretty jumpy about any changes to its normal function.