Excel opening a certain file instead of blank workbook when entering program

It is possible that you accidentally put a file in the startup folder. Every time Excel starts, it will automatically open every Excel file in that folder. You can check. Go to

File, Options, Advanced, scroll down to General, then look at "At startup, open all files in"
Then go to that folder and see what's in it.

I have mine customized; most people don't. But I don't remember the default, so I recommend you look it up as above.