Welcome back!
Did you used to have other peripherals hooked up? CD drive, etc.? If those are absent now, any startup software that was expecting them might be hanging.
Others mentioned booting from floppy—the fact that that works is a good sign. You can also hold down both mouse buttons early in the boot process to get to Early Startup Control. From there, you can boot with no startup sequence to get into a command Shell. Whether via shell or floppy, you’ll want to look at the startup-sequence and user-startup scripts, along with the WBStartup drawer. I suspect the issue is in one of those locations. It might also be something in Devs:DOSDrivers. Let us know which avenue you want to investigate first and we’ll talk you through.
Boot without startup-sequence, first <Assign Env: RAM:> to suppress Env requester and then <LoadWB Endcli> to launch the default Workbench which you then can check for problems.
