Ok, lets think this through: Even if things were deleted from the Taskbar/Task Manager, that shouldn't matter as far as the display is concerned; the driver would restart the next time Windows boots. And even if the driver was outright deleted, you'd still get low-res output of the Desktop. Likewise, you should be getting BIOS/Windows startup display unless something is physically wrong with the GPU.
As such, this sounds like hardware. So lets isolate.
Does your PC normally beep at startup? If so, is it doing that now? Wondering if the PC is even getting past POST. Failing that, try plugging the computer into a different display (even a TV you may have lying around). Key point is to isolate *where* the problem is: PC or display.