What version of DevC++ were you using when you created the original projects? What current fork of DevC++ are you using now?
Orwell's fork still works with Win10, though the embedded C++ compiler is about 8 years old.
[ETA]: Well, Dev-C++ 5.11 doesn't work with Win10 any more when creating 32-bit apps. Windows now blocks execution of the 32-bit app.
I tried to compile using Embarcadero's fork of Dev-C++, no joy though the compilation successfully completed.
Apparently the only viable (and easy) option left for WinBGI is to use Visual Studio. I know that works. I was able to use the VS2010 sample, letting Visual Studio upgrade the project/solution.
All the WinBGI source files needed are included, and I was able to get the Dev-C++ sample to work.
Substituted the contents of main into the VS WinMain, and nice purty WinBGI window with a circle and a title bar of "First Sample" was displayed.
Seriously consider taking some time and make an effort to install Visual Studio 2019 or 2022 (2022 recommended) so you can mash your old Dev-C++ projects over to MSVC.
VS and Windows were designed to work together, playing nice. Dev-C++ even with the newer forks are antiques.