Computer does not turn on

If you have verified that your power source (wall plug) is decent, it is most likely a worn out or weak power supply. What is the brand name and wattage of the power supply and what video card are you using? Do you know someone who has one you can slip in there to try?

Power supply brand is BESTEC model ATX-250-12v. Input 100-127v 6a. 200-240v 3a. Cannot make up my video card.

To be quite honest, that is one of the worst power supplies around, so that kind of tells me that should be the best place to look for the problem. Do you have a spare or a friend who has one you could try in there?

If the the power supply is the culprit, what do you recommend be replace with?
Unfortunately don't know anyone would have a spare one to try see if that is the problem.

That (according to specs) has an onboard video card, so this one should work:

Newegg.com - SeaSonic S12II 380B 380W ATX12V v2.3 80 PLUS BRONZE Certified Active PFC Power Supply

If you could also find a Corsair in the 350-400 watt range, it would be fine also.

If you have a bestbuy nearby, they have the brand name Corsair (excellent quality), so go and find one there and try it. If it doesn't do the job for you, return it. The local store does not even charge for restocking, so that might be a way to make sure without putting out anything. Of course, if it works, then keep it and problem solved.

Went to Best Buy and bought a Dynex 400- watt power supply. They did not
have the one you suggested. Installed it and what a joy it was to see my computer working again. Thanks for your help. Job well done.

Don't count on that Dynex (very poor quality) to work for long. You need a good quality unit to prevent damage to your other hardware.