You don't have to ask anybody else. Your bank already told you the truth, why don't you believe them? Do you really believe someone is going to 'give' you huge sums for nothing, or in a fairy godmother??? This is absolutely, unconditionally a "Nigerian check scam" that preys on the naive, gullible, ignorant and greedy.
You are supposed to deposit the check and then pay out all that deposited money in a check to someone else. I assure you that the deposited check will bounce NSF after a few days or weeks, leaving you owing your bank that money, which they will automatically take out of any account[s] you have, or sue you for it and win.
If you still don't believe, merely have your bank deposit that check 'for collection' into a brand new account you open with nothing else in it, and wait until it actually clears or bounces before paying out the money as instructed by the scammers.
If I am wrong, please contact me and laugh at me if you actually get your $45k and can spend it.