Your computer must be having a hard time reading the amount of RAM on your PC so definitely a problem.
Open up the computer and make sure the RAM chips are firmly in with the clips on the motherboards RAM sockets clipped onto the RAM through a hole, or a space on the RAM chip for it, which tells you its attached right.
If your not sure, take the RAM out and reinsert it,being careful but keep pushing until you hear a click sound to tell you the clips have moved into place on the chip.
Have you by any chance bought some new RAM though? Maybe its incompatable with your motherboard, or it could be a RAM chip that has failed on you.
If you have more than 1 chip inserted, take one out and try it, and then switch if this doesn't work. Any improvement?
If this helps and it boots, simply replace the faulty RAM (unless this is the new one you bought, in which case, find out what your the RAM chip speed is and simply exchange) and then you should be up and running again.
This problem can't be anything else,so must be one of these suggestions
I hope this helps