RAM failure makes the BIOS sound a beep code.
If youre not hearing beep codes, it's more likely the Power Supply, or the processor overheating.
Try accessing the BIOS.. if the screen remains on after a few minutes, it’s OK, but if it shuts down when you’re in the BIOS, it’s overheating. To make sure (and solve) check if the processor cooler is running, that the heatsink is firmly attatched to the processor, that immediately after a failed boot, the processor heatsink is cool-to-warm to the touch, not hot.
If all check OK; the Power Supply may have failed.
If you're experiencing one or more of the following problems, the Power Supply is likely the cause:
1. Momentary freezes that last from tenths of a second up to several seconds
2. Slow Explorer
3. Sketchy mouse pointer/cursor
4. Long boot times
5. Booting under a blank screen
6. No booting, or interrupted boots, booting on the second try
7. Memory errors
8. Slow memory
9. Slow processor
10. GPU with blank screen
11. blue screens of death
12. spontaneous reboots or shutdowns
13. Bulged and or blown capacitors
14. Bad hard disk sectors
15. Slow Internet browsing