T2984 won't start

[cke]

Here's the scoop. My emachine, 4 years old, would restart itself a couple of times a day for about a month. All of a sudden today it wouldn't start. Nothing. I changed two power supplies and nothing happened. When I put back the old power supply, Bestec, something strange happened. The two fans ran for about 5 seconds and I noticed a red light blink on the Mother Board but the unit doesn't start. Any ideas. Thanks

Charlie