MacBook Pro does not power on sometimes I have a MacBook Pro 15″ Late 2008 (5,1). Sometimes it just won't power on. It works fine. I shutdown, then when I go to turn no it just does nothing. Previously I removed the battery and the charger, pressed the power button for a few seconds (so as capacitors can decharge etc) and then it powered on. The last 2 times, I couldn't turn it on for two days. After two days I just pressed the power button and it turned on. 

Note that no water has been spilled or anything like that. Are there any recommendations? Any known issues with workarround?
Could be as simple as something making the power key stick - I used to have this problem with my 2008 Macbook Pro 15". If you dropped it in the past this can cause wiring to come lose (had this problem too!) despite everything else appearing to work normally.

Definitely get it fully backed up ASAP and then have it checked out.