i have the same problem. MC Mods worked fine before. i haven't played maybe 2 weeks and now nothing works. i click the "play" button, some text flashes where the button was, button "play" is back. No MC window opens up. no error message. just nothing. i have allocated 8 GB for MC. didn't change a setting, so ... no clue.
edit: i can start MC mods just fine, using the ftb launcher (which doesn't have the one i want to play right now) so i guess, it is not a "reinstall windows" problem but one of curseforge.