Good afternoon. It's my pleasure to try to assist you. What's been going no with your Mac? And how long have you owned it?
Yes, anyone is here. It takes a few moments for the messages to refresh. This is an extremely busy Web site.
What is the EXACT problem you're encountering now? It isn't clear from what I'm reading in the question/answer panel.
If you are having sporadic problems powering on, and you notice inconsistent behavior when you plug/unplug the power cord, you likely have a power supply problem.
I see you just posted "third time O.K." I trust you realize that these kinds of situations degenerate; they don't improve. If it's going to start every third time today, it will be starting every sixth time next week.
Power supplies often go bad because power transformers (which change the 120V wall current into the 15V needed by your computer's CMOSFET circuitry) are very cheaply built. They use low-grade magnetic alloys that lose their hysteresis characteristic after being charged/recharged many times. (Remember, when you plug into wall current, the transformer's magnetic core is being charged/uncharged/recharged SIXTY TIMES EACH SECOND.) Presently, the circuits aren't getting enough power to switch on--until the thing cools off or, because of some happenstance, is just above the threshold to turn on.
Bear in mind that your computer has its OWN transformer, IN ADDITION TO the one in the charging cord.
Did you purchase a maintenance plan when you bought the computer? It's always a good idea to back up a pricey investment like a Mac with a one- or two-year maintenance plan. From what you're saying, the Mac is several years old, and it's way out of warranty!
It may be worth having the Apple technicians look at the power supply. It is POSSIBLE that a damaged power cord can cause oddball behavior as well. I will assume you have invested in a new power cable and tried that--not to "throw good money after bad," like a mechanic who rebuilds your car piece by piece until it "works better"! Replacing a power supply inside a Macbook should be doable for under $150.
WARNING: they will go on and on about how the unit is archaic, how the new Mac is so much better, faster, sharper, etc. DON'T fall for that if you are happy with your computer. Plus, it can be a major headache to migrate to a new machine if you've been using this one for years.
O.K. Forgive me if I check the "Ready to be rated" box. Not trying to pull a fast one. It wasn't exactly rocket science. Good luck!
PCs are much cheaper than Macs, as you know. They're also much shoddier. That's a trade-off, obviously.