Make sure you have the computer unplugged from power and disconnect the battery while removing or moving any hardware...
Try 1 stick of ram in 1 slot at a time (remove all other ram sticks). Move it to the next slot until you have tried that stick in all slots by itself. If you still have no post, try a different stick of ram in each slot by itself. If you have issues with the stick in 1 particular slot (a no post for example) the slot may be bad. It is also possible you have a bad stick of ram instead of the slot being bad, in this case the ram stick should cause the same problem all slots.
You may have a memory controller issue in which case if you have 4 slots, 2 may not work. With intel it should be 2 slots next to eachother channel 1 might be slot 0,1 and channel 2 might be 2,3. Trying with 1 stick at a time in all 4 slots is the best way to test everything.
If you never get a stable system with just 1 stick of ram in 1 slot (trying all sticks by themselves) try removing all non essential hardware to get into bios:
Disconnect pci cards, wifi cards, hard drives, dvd drives, web cam etc. You should only have the power supply, main board, 1 stick of ram in 1 slot, the cpu and cpu cooler connected. You can also plug in the built in monitor. Now try to power on the machine. If at this point you have no post screen or video etc, unplug the computer and pull the stick of ram, power back on and listen for a post fault beep code.
If you get no response next: remove all of the components from the computer case and connect only non essential hardware outside of the case, place the motherboard on a non conductive surface, a wooden table will do fine. Then try to power on again, you can short the power button pins on the motherboard, don't worry this is exactly what the power button does. Just touch a metal item to both power button pins to try to power the mainboard when outside of the computer case.