PC going on and off

Hello, I turned my PC on after a long time it started and a black screen appeared saying "Firmware has detected a CMOS battery failure" i continued and it didn't go past the black screen so i replaced the cmos battery but now the computer wont even give any display it turns on and off no display to monitor or keyboard or mouse i removed RAM to check if it was faulty the cpu gave continuous beeps what should i do now? these are the things that i have checked:

GPU is working fine
Monitor is Fine
Changed RAM and also the Slots

Please help guys.