Computer boots but no display

[dan macduff]

Hello,
my computer bootbut no display. it worked fine for 2 weeks before i went back 2 school. i tried replacin the memory/video cards, another hard drive, another power source, another monitor, booting w/ no devices and another cpu please help. could it be a virus?

 

[JackNaylorPE]

Checked the OSD on the monitor (on screen display menu) and made sure that yu have correct input selected ?