boots w/no display

My computer is booting but, there’s no display, it works sometimes however.I have to turn the switch on the back to shut it off then turn it on in the front.I installed a new display adapter and this did not fix it.Same symptoms.I tried the reset button a few times and now the hd LED stays lit and cant get it to come on at all.Also when it did come on, I could’nt restart it,no display, I could here it rebooting but no display.It’s a pentium 333mhz w/ win 98se
I did install the display adapterproperly.