Having this same problem with a mid 2010. I had had both the battery AND the logic board replaced under the little known video card problem just before the 5 year warranty expired as I paid the $300 lump sum. I took it back claiming that the parts should have had at least some kind of their own repair warranty with no luck.
I have also tried the SMC and PRAM multiple times.
Sometimes the battery disappears form the upper right in the screen, other times the Wireless icon disappears.
I have upgraded to a solid state but there were no problems up until I had all of the warrantied items replaced.....
Help!