If BIAB is an old 16bit program and you have updated to Window 7 64bit that may be the problem. Switching to Window 7 32bit might be easier. There are options to get a 16 bit program running on Windows 7 64bit. These might help..

https://www.pcworld.com/article/2045345/run-an-old-program-on-a-new-pc.html

https://www.researchgate.net/post/How_can_we_run_16_bit_applications_in_windows_7_64bit

But this looks like a lot of work. Probably finding a way to get a new version of BIAB would be the best route.

Andy