May be an issue with the windows wallet, I just restarted it to check if mine was having the same problem and it says
that the block chain was corrupted again and must be rebuilt.

I'll let it do its thing, then restart it again to see if I have the same problem.

edit
Yep, same problem again, rebuilt the blockchain and synced, I then shut the wallet down and restarted it and once again, I have to rebuild