Help computers

Computer will not start, black monitor.  It use to freeze on motherboard logo, now black screen.

I have a old single processor with 2700 ram, and agp graphics card.  Worked great for what i was using it for.
I know its not ram, harddrive, or graphics card

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no really help, helping me is only going to help busineses in town

Unplug everything from the USB ports and try again…