I've had a few times now when Comfigurator 3.6.2 appears to hang on the splashscreen and looking at task manager it doesn't appear to be using and cpu.
What it seems to be is that the upgrade dialog box is flashing up and hiding behind the splashscreen rather than being on top.
I'll upgrade to 3.6.3 to see if this fixes but though you should know anyway as if you don't happen to be looking at the screen at the second the upgrade dialog flashes up and hides you can be sat there thinking it has all hung.
It seems that a 15s timeout if your Internet connection is down is also a bit long. Why not 'thread' the check for upgrades and continue to load the Main Comfigurator. Once an update is available then you can display it on the screen.