I have that written up but like to use 60 seconds as I found folk tend to not hold the button long enough.

ISSUES!!! At 6+ years it may be gone but here are the issues with old laptops.

1. Batteries. Yes more than one. You have the big one that must not be over 2 years old or I turn the unit back to the client if they try to get by with 2+ year old batteries. Why? These can overtax and kill the mainboard's battery circuits.
2. Battery number 2. There is usually a CMOS battery and on some models if it gets too low, the laptop does not start. It's 2 to 20 bucks well spent. I have seen folk DEMAND that I warrant that's it. Sorry folk, it's not that sure that I can call it everytime. But it's a cheap gamble.

3. I wonder if the charger has failed. Try another.

After that I start removing what I can in hopes it's some part we can replace and get more time out of the old machine. I'll unplug the wifi card, ODD and HDD and leave just one stick of RAM in it. and try the generic reset again.

No guarantees here. It's done well to get that many years.