^^ Honestly you really need to re-frame your sentence. Forget for now what happened that night and say what's happening now.
Did you do a CMOS reset? Keep that 4 pin ATX pin connected on the motherboard at all times. What are the memory kit that you're using? Have you seated the heatsink properly (I would do it again as patiently as possible- also make sure the pins are not damaged- and/or proper application of thermal paste)? Reseat memory stick properly or use the other DIMM slots on the motherboard?
You'll need to do couple of things which will require another system. Google and download memtest86, there should be a readme file on how to make it as a bootable disk in a flash drive. Follow the instructions and boot using hat drive, run memtest for about 4-6 hours on your system. If it shuts down, there's a problem with the memory- possibly either the ram or the slot- or worse case scenario- both. If it does and/or doesn't, connect your hard drive in another system as a secondary drive, google and download HDTune and run an error scan. If it shows any bad blocks, RMA the drive. Do both and let me know. Make sure you reset CMOS and check the processor, reseat them again properly and keep the memory stick(s) connected on the other coloured slot.
If you can't run memtest in the first place, swap the rams with another slots on the board. If that doesn't work, try with 1 ram at a time. You'll have to take the headache of doing all these steps in a proper flow to narrowing down the issue(s). Make sure you have the time and patience to do. Use this as an opportunity to learn one thing: can't afford a decent enough psu, don't buy a pc.