They are a pain to work on... I would either buy another one or Garmin has a repair depot. They will replace the Battery and fix/replace the screen but it might be cheaper to get a new one. Wait for black Friday :)
Have you replaced the O2 Sensors? (BTW you might have more then 1) They control the fuel/gas ratio so they can really jack stuff up if they are really old or clogged up with gunk. BTW you cant clean them, you have to replace them.
Might be a heat issue... If its the old model (non-slim) PS3 then it may just need to be cleaned out with a can of air. Also check to see if the fan is working, when you turn the power on check to see if you feel any air coming out the back of the system. Hope this helps.
Make sure the laser is clean. Not sure if you want to take it apart but if you feel like its something you can tackle then clean the laser (with the power cable unplugged) with a Qtip and rubbing alcohol 70-99%. If that fails you will need to replace the optical drive. There is a kit you can buy online to do that.
Make sure that nothing has dropped into the feeder, also see if you can unplug the printer, open the door where the ink cartridge is and see if they will move on the running bar. Gently push them from side to side, if they don't move at all, you might need to get a new printer from Walmart or something. Since you have not used this printer in 2 years I would just recommend doing that if you don't want to troubleshoot it...
Sounds like it could be a power supply problem... This model had some issues with that happening. When the system is running for a little while the parts located on the power supply begin to expand (normal) but sometimes they lose there ability to send "constant" power to the system so it will shut down.