Hard disk will be fine, just remove and stick in a usb case.
Suggest find a repair place that does board level repairs - there are some around. Check gumtree.
Your average PC store won't be a good bet though, as they're clueless, and will probably damage it.
You can try a different PSU - just make sure the voltage is the same or within about 10%.
eg - if you have a 16.5V@3A PSU, another 16.5V PSU is fine to try. Amps don't matter - as long as its >= its ok*
*Simplified somewhat, but ok for you to test for a minute or two.