Unfortunately I can't help you with your problem, but I suggest looking at the computer group and starting a topic on there. You can usually get a response within the first few hours and the people in that group are fairly knowledgeable.

Ok, i think its not the computer, its the charger! My macbook go trough that phase, but... it cost me 100$ to get a new mac charger.

You have to go to mac-store to support

Pretty much everyone I know with a Mac has had the charger break on them and like the last guy said it is expensive. Other than that I have not heard much about any other mechanical problems with them. Maybe try eBay or something to get one cheaper. If you know someone with a Mac borrow their charger to see if it helps?

Yea, that also happened to me with the charger and it was the charger. I found a new one for like 20$ on Amazon.com. everywhere else they were like 70 to 100$ I have no idea about the rest.

Apple store will usually replace a charger for free if you bring it in and show it's not working.

Like others have said it probably is just the charger. I had the same issue with mine. The other stuff is also caused by the charger cuz when a computer Mac or not is shut off improperly such as power failure and so on its very rough on the hard drive. Which can lead to your comp going back to a default format and sometimes will misplace or even lose some files.

On various non-apple laptops I've had great luck by removing the battery and then holding down the powerbutton for 15 seconds to remove any excess power still in the laptop, then after plugging in the battery it will charge again.
Having no apple experience I got no clue if it's even possible to remove the battery.
Could be worth a try since it sounds like the same symptoms many of my users have.

But then again, if it used to work after wiggling the charger cable it sounds like a loose connection. Above solution have solved some of those issues where my first thought was loose connection tho.

i think a new charger needed and then restore your computer to a previous date when it was working fine, then do your updates ... aswell as a virus scan ..hope you get it sorted hun xxx