I have a HTC Desire X that refused to switch on after it was switched off. When I plug in the charger, the orange light came on but it still wouldn't switch on. I left it to charge overnight but the next day the light is still orange and not green. 

I tried the following but they didn't work.
- Press the power button for at least 30sec
- Press Vol Down button and Power button for 30sec
- Connect to laptop
- Change USB cables
- Use a different charger

I bought it about 18 months ago. I think it is still under warranty. I'm apprehensive of sending it for repairs without doing a factory reset because there is lots of personal stuff in the phone and most of the apps are never signed out. But I can't do a factory reset without power.

Any suggestions what else I can try to figure what is wrong?  I hadn't dropped the phone or be rough with it.

If I have to send it for repairs without doing a factory reset can I just put a magnet over the phone like what people do with harddisks to destroy personal information?