I just upgraded from Win7 to Win10 and Girder 4 no longer starts up. This error message is shown:
For security purposes, this program will not run while system debuggers are active. Please remove or disable the system debugger before trying to run this program again
This thread may have a solution (I am not allowed to post full links, please prepend the appropriate showthread questionmark url):

where Ron says:
If you are refering to G4 I had to increase the level of protection on the executable, contact me if you want a executable that allows you to debug.