Try deleting just peers.dat and restarting first, your client may still be trying to connect to users on the old wallet, but there now blocked from the network.
Unfortunately deleting the peers.dat file wasn't enough. I had to delete everything but my wallet.dat, and .config file (which just contains the addnodes in it) and then re-sync. After that I saw that the majority of my coins were missing, so I went into the debug window and typed repairwallet. After a moment I got:
14:28:32 repairwallet
14:28:48 {
"mismatched spent coins" : 2252,
"amount affected by repair" : xxxxx
}
where "xxxxx" showed the actual amount. After that I unlocked the wallet, and it started to stake like mad! Everything seems to be OK at this point, but man that last moment where most of my coins seemed to be missing was scary!

Edit: I also have noticed a weird group of failed stakes starting on Friday the 25th up until I the time I finished re-syncing and unlocked my wallet again today in the transaction history (over 8,600 transactions).
BTW Bitstar_coin I noticed something. When I click the Unlock Wallet button in the lower right corner of the Overview tab, the pop-up window that asks for my password doesn't have the check-box to unlock for staking only. Yet when I click the Unclock Wallet button in the toolbar the check-box IS there. (I haven't checked the Unlock Wallet menu item in the Settings menu yet.) Is this a small bug?