There are several questions that need to be answered which would narrow down the possibilities, but you'll probably have to have diagnostics done to detaermine what's wrong and f it can be fixed. In that case, places such as Best Buy would charge you a nominal fee (~$50) to test it for you.
If the computer's only 4 months old, and you bought it new, the tech is an idiot...4 months, at least the last time I checked, was less than a year, meaning it's still under warrenty! Call back and get someone who speaks English or check their website and jump on the real-time online chat...I've found the support from them to be much more satisfactory.
The fact the warrenty is still valid is, unfortunately, not a factor here, as it does not cover acts of God, such as power surges....that's only covered by the accidental insurance policy. Since the problem has already happened, purchasing the insurance would do no good...it's too late.
Was it plugged into a surge protector? (Everything, including the power cords, phone line, cable, etc) If so, see if the surge protector has a warrenty that coveres connected equipment. If so, they will most likely have to reimburse you for any damages that occurred.
When you press the power button, what happens?
* Does the light on the front turn on?
* Do you hear/see the fans kick on?
* If you press the button for a CD-ROM drive, does it open up?
* With the monitor on, does the monitor's power button change colors?
* Do you see the BIOS screen? (It should show either the HP logo or a bunch of stats)
The green light blinking on the back...is it the one next to the fan towards the top? If so, try completely unplugging your computer, flipping the little switch back and forth between 120 and 240, ending in the position it originally was, and plugging it back in. Sometimes you'll get lucky an that will help.
With any luck, the surge only damaged the PSU (power supply unit). If that's the case, you can replace it for ~$40 and be on your way. However, there's also a good chance that the surge traveled throught your system, frying everything in sight. In that case, the motherboard, processor, optical drive, etc could be shot, and your hard drive, including all of your data, could be totaled. (I hope you have backups, as there's a possibility this could turn out really ugly.)
Hope this helps and let us know more.
P.S. Don't worry about posting in the wrong forum...it happens, especially when you're stressed. This is actually a hardware issue, but let's just continue on in this thread instead of starting over.
This a 4 month old Presario running XP. As per manual instructions, I called HP support and of course got a foreign gentleman that I couldn't understand. He informed me rather quickly that the machine would be out of warranty in a few days (warranty book says 1 year) and that the problem occurred because of a power surge and it was not covered. If I purchased accident insurance and ex warranty it would be free. This would be $199 or HP would fix it for the same price. I say this is bullcorn and if you know of any other possibilities for me to try, please let me know.