Ok, I have been waiting for weeks for the Fork to PoS. Last Friday it stopped synchronizing so I immediately went for the new Wallet. 50% PoS!! BUT.. New wallet ignores the old wallet???
What to do, I'm rather panicking by now

If I try to copy the old wallet to the new %AppData%\MMXIV2 folder, all I get is:
A fatal error occurred. MMXIV can no longer continue safely and will quit.
EXCEPTION: NSt8ios_base7failureE
CDataStream::read() : endo of data
C:\Program ...\MMXIV-Qt.exe in Runaway exception.
twitter.com/devnullius
The old wallet and new wallet are on different blockchains, the wallets are not compatible. You need to send a PM to MMXIV to get your coins swapped over to the new chain (this REALLY needs to be in the OP).