I have an old desktop with AMD-Athlon X2 processor and ASUS M2NPV VM motherboard.Since yesterday afternoon when I switch it on , it boots properly and works fine for few minutes and then powers off. A week back I added 1 GB RAM (total 2 GB RAM now)and cleaned up thermal paste and applied once again. It was working fine till yesterday . Also when I enter BIOS setting on start up , it doesn't power off. What could be the issue ?