I've seen this before, but I forget the particular issue. I'd try these options:
Before you try my listed items below, maybe take a look here and see if this is the whole problem:
I don't think it is, but just in case.
Also, I think it can sometimes SOUND like fullscreen vs normal screen mode, which I do not think is the issue. But if you want to check that out as well, here's that link:
Now for a list of items I think MIGHT actually work. The one I'm thinking is the best one to try is removing files from your appdata folder/directory.
[ol][li]Try opening Excel in safe mode: Here are some instructions I found:[/li]
[ul][li]
[/li][/ul]
[li]Probably won't work, but try [Aly]+[F] to open the file or formerly called "backstage" view/menu and then [T] for options. If you can get in here, look for default options within the Excel options. One idea, maybe, is Advanced: Disable hardware graphics acceleration in case there's an issue there (Under Display). There are other options to try as well.[/li]
[li]Again if you can get under File (Or in 2007 it was just the round button at top left) -> Options -> Customize Ribbon - see if everything is somehow unchecked (this is just a wild guess trying to think of possibilities.[/li]
[li]With Excel closed, try moving ALL files/folders under
C:\Users\<YourUsername>\AppData\Roaming\Microsoft\Excel to some place like a new folder on your desktop. Then try to open Excel again. MAYBE look at files in the same path, but "Local" instead of "Roaming", but I think you'll find no help there. And there should not be such a folder under LocalLow, but if there is might as well give it a shot. If removing the files/folders works, the only thing you most likely will need to put back is a PERSONAL.xls or PERSONAL.xlsb file if you have either of them in the XLSTART folder. Really anything in that folder in case you have some other file(s) there. I'm guessing you have none, since you say no macros.[/li][/ol]
Those are just some thoughts. I wish I could remember the definite exact fix. It's probably been at least 7 or 8 years since I used Excel 2007. That was first year of the ribbon and the ribbon functionality was greatly improved beginning in Excel 2010.
"But thanks be to God, which giveth us the victory through our Lord Jesus Christ." 1 Corinthians 15:57