The important thing is keep clam and BACKUP your WALLET !
If you can see the correct balance with the blockchain explorer the coins are on your account.
Back up your wallet and install a new  on a different computer, syncronize !! and restore your wallet.
You can also restore before sync, importand is that it is completly syncronized.
I had a similar problem, even creating an other user on the troubled pc wasn´t working.
Due the lack of a missing second computer I had to use the same machine. At the end it worked well, but I realy was worried till restored my coins.
Took me 62 days by the way.
Hopefully you will be much faster.