Should have posted before ordering a new flash card. Gamekingslots.com doesn't have a very good reputation here on NLG and has been banned. That said, I hope you get your flash card and that it works. If not dispute it with your credit card company.
Check with member RB, there's a bootchip that allows you to bypass the SHA checks and that may get it working again.
It's doubtful that plugging it in with the power switch on hurt anything. Letting it sit turned off won't hurt it either. Mine spend the winter in an unheated garage here in Michigan and stay shutdown usually until spring. Sometimes I'll fire them up to check a setting or get information to help members here. The bill validators are sluggish in cold weather, but the machines have always been fine. I certainly don't baby them any, and the keep on going. Hard to say exactly what happened with yours, but I doubt it was due to anything you did.
You don't see a lot of 044 flashcards advertised for sale. I hear or read something somewhere that IGT offered some type of credit to casinos in upgrading their machines if they turned them in. Not sure if that's true or not. 044 MPU boards seem to be readily available though. Spare parts are always a good thing to have.