Once again remove the RAM from the slot, clean it and place it back properly
or try another slot. Check you RAM also. Even bad RAM will result such problems.
Check if you are able to get the display from the onboard VGA.
Even if,it will not work then try this one:
1) If you are sure that you are getting the beep, beep, beep [pause] and your RAM is working in an another PC then check your memory module (RAM Slots). Clean it and place it back properly.
2) First remove your video card andt then try resetting your BIOS settings.
Turn off your PC and remove the power chord --> Open the cabinet --> Remove
the CMOS battery for 15-30 minutes and then put it back properly. Now plug the
power cord back in and switch ON your PC.
Click on the below hyperlink "CMOS Battery" if you don't have any idea about the
If the problem still exist, click on the below link and follow the instructions in "Hardware Reset".