I have an old HP Computer and have had it running for 8 years...sometimes a program I have freezes up so I shut it down then turn it back on...this time it would not turn on...advice..did it finally die...did I loose all of my info on it??? Help
Most likely the power supply has died based on your symptoms. There is a possibility that the motherboard has died as well, some older HP models were plagued with bad capacitors that over time dried up and died.
It is possible that your data is still there on the HDD. If you are not sure how to do this, I'd advice you to see a local computer shop to have them take care of the diagnosis/data retrieval for you. This is incredibly common, and the techs will know what to do.
If you feel comfortable doing it yourself, you can try swapping a power supply unit, visually examine the motherboard capacitors and try removing the HDD (absolutely do not shock it, or drop it), and reading it on another computer or with an external adapter. If none of this sounds simple for you, then see that tech....