No boot-up at all

I've been going through the forums but haven't ran into my problem so far. I live in Ohio and a couple of weeks ago we had a bad storm, trees were toppled over by the roots, high winds etc.The electricity kept cutting off and on for about 4 or 5 times until it finally went off and stayed for a number of hours. I have two pc's and they are both on surge protectors. The one pc will no longer let me log on with the Mozilla browser even going back to several restore points. I figured I can just uninstall that and reinstall and hopefully I will have no more problems with that one. The other one, however, will not allow me to boot up at all. If I turn it on it might start running for about 15 seconds and then it cuts off. Is there any hope for that one or is it fried?!!! I've had it for about 5 years. That pc is a Am-Comps /Pentium 4 1.7/GHZ 256MB DDR. I let my grandsons do their homework etc. on that one but they are not allowed to touch the one I'm on now. I'm wondering if it is salvageable or not? Should I take it to the shop or is it worth it. I've had problems that the tech support have walked me through in the past but I haven't the slightest idea as to where I should start.