Your post suggests that you have one or more of the following problems:
1. Bad RAM
2. Bad PSU
3. Bad mobo
4. short to ground
The first thing you should try is breadboarding your system. To do this, follow these steps:
1. Remove everything from the case.
2. Put mobo on a phone book, or other non-conductive surface.
3. Install ONE RAM stick.
4. Connect PSU (both the 24-pin and 4/8-pin CPU).
5. Jump the PWR_SW pins on the mobo using a flathead screwdriver.
Do you still hear the beeps? Has anything changed?
If no beeps, turn off the system by flipping the PSU switch, and then install your GPU. Don't forget the 6/8-pin supplemental power connector. Turn on the switch to the PSU and jump the PWR_SW again.
If no changes or no display, turn off and change out the ONE RAM stick for another ONE. Turn on and try again. If still nothing, change the RAM to the last stick.