XPS 8300, power issue

I had a temporary loss of power at my house and now my XPS won’t power up.  This happened to me about six months ago and I don’t think I really did anything to fix it but it seemed to resolve itself. Basically nothing happens when I hit the power button. If I hold the power button down, there is a solid green light on the back of the tower which comes on. If I push the power button briefly, the light on the back goes off but no matter what I do it won’t power up. I left it alone briefly for a few minutes and heard a beeping noise. I went back in and the power button was amber and flashing and beeping four times. I unplugged  the power cord, waited a while and plugged it back in. The beeping stopped but now I have the same issues with it not wanting to power up and the green light on the back going off and on depending on how long I hold the power button down.