Dnload an run memtest from  www.memtest.org/ Tests 5 and 8  if it errors it is the memory..Reseat try again.
Unplug all powered devices but the basics hd ,video card ,1stick of ram, cpu etc...
This includes usb devices.
Sounds like the powersupply is about to give up the ghost.Try a known good and compatable one.
Take battery out overnight ,next day ,boot get into bios and select the default setup reboot.
Try a plugging into an outlet in another spot in the house.That outlet may be browningout or undervolting  the powersupply ,a good PS can overcome this but a weak PS will fail intermitantly .

"Reinstall Windows" is NOT a troubleshooting step.