Hmmm.. Is this 32 or 64 bit windows? And this is only with the QT wallet right? Can you try downloading thehashcoind and thehashcoin-cli, running thehashcoind and manually unlocking with the CLI?

Also when you say "unlock" do you mean decrypt it permanently or do you mean unlock it temporarily to send funds?

Let me know what goes on, we'll get it straightened out!