The answer is- are you nuts?- absolutely do not try to refurbish a fried DVD player that is five years old.
I agree that you should use all your coping skills and move on.
This is not a very expensive item to buy right now in view of the obvious conversion to blu-ray. You can buy one that cost $250 when first marketed a year or so ago for $60 at your local big box store or internet "electronics" vendor.
It is no where new BTW you had current in the circuit for ?how many hours? Even if unplayed, you have thought you could have burned something out.
With regard to leaving things on I used to do that, but now I don't . The reason is most of my stuff is tube and I use pretty good (read cost too much) tubes. A respected tube dealer and Citation restorer/modder Jim McShane on tube asylum thinks it is a sin to consume great old tubes by leaving them on idle. The downside is that of all things tube equipment takes the longest to "warm up". On average it takes an hour minimally to be in the best playing condition.