No monitor display, 1 long beep, 3 short.

I apologize in advance for the slew of questions im going to be piling on here, im not exactly good with these things. :(
Anyway, my PC was working fine for a while, occasionally theres the "graphics driver has stopped responding" error when using AutoCAD,
and just recently after a windows update, it started having problems waking up after Sleep mode (manual and auto). Everything runs fine, the fans, hdd etc, but no monitor signal.
And after some googling an tweaking, another problem started, and that is, when switching on my PC, it gives 1 beep, followed by 1 long beep and 3 short.
Im using Asus M5A97 LE R2.0 mobo. Ive read some solutions on various threads and sites ( sometimes not fully understanding them unfortunately) and the difference between mine is, sometime after powering down, turning of the power completely and the on again, it starts up just fine, and still has the sleep problem however.
Most solution mentioned problems with the graphic card and the Asus manual states the beep indicate ' no VGA detected '
truly at a loss here, much appreciate the help.