Suggest we start with the simple stuff first, Ken.The two major issues with desktop computer failure, is;1) The computer is dirty inside2) Power Supply is badThe two kind of go hand, in hand; so it's logical.I see by your statement/s that you believe this is software related.I believe it is hardware related.Follow Anti-Static Procedures, and let's take a look 'under the hood'.Your body carries Static electricity. Static WILL fry out (Short Circuit), the delicate hardware components inside a computer.Relieve your body of Static BEFORE reaching inside your computer.Computer on a table, computer unplugged from power, computer case open;TOUCH an unpainted surface, of the metal frame of the open computer case.This action will relieve your body of Static.IF, you leave your computer in the middle of working on it, be SURE to Touch the metal frame again upon your return.Moving on................Lenovo Support > IBM ThinkCentre A50 Desktop PC > HMM(Hardware Maintenance Manual),
http://support.lenovo.com/en_US/downloads/detail.page?&DocID=HT035401I don't know which Machine Type you have.(Not even sure if it makes that much difference, actually)Go down through the list, and click on the appropriate ThinkCentre A50 in blue, with the correct Machine Type to the right.On the next page click on the Down Arrow, under the heading -> Download now.(Or you can click on the blue file name, to the Left)Ignore if you are aware;This is a PDF file. The computer you are using now has Adobe Reader on it, which uses PDF files.After you click on the down arrow, it may take up to 30 seconds, before the first page comes up.A PDF file will not show until fully downloaded.This is a Temporary download. If you wish to save it to your computer, and do not know how to, post back in a Comment.After you download it to your computer, you can burn it off to disk for safekeeping. (Or flashdrive, yecch)Then after checking to see if it is a good copy, you can delete it from the computer you downloaded it to, and save harddrive space.Also, happen to have access to an inexpensive multimeter, or a KNOWN to be good, Compatible power supply? Post back in a Comment.Regards,joecoolvette