Cannot log on to computer

Question

Hello,

I installed this product on my computer and was going to transfer my files to another computer. I was at the undo screen on the old computer because the new computer wouldn't accept the software. I hit undo. I was then going to uninstall this product. Instead it reverted to an old administrator password that I don't remember and I cannot log on to the old computer because it won't take my recent password.
What do I do to fix this?