When I re-installed the client a while ago, I found it just installed a second copy of the software, rather than upgrading it.
So you might find you have 2 versions of the software installed - one pointed at the old wallet, and one pointed at the new.
ahh .. explains it ..
go to "%APPDATA%/Roaming"
you will find a folder "BitShares X" which contains your OLD wallet
and a "BitShares" folder .. that one contains the 'new' wallets ..
rename the "BitShares" folder to something else .. better not delete it .. for safety ..
then rename "BitShares X" to "BitShares" and start up the client again .. it should start with reindexing the database ..
give him some time for reindex and resync ... MAKE A BACKUP afterwards too !!!