IceWM captured my computer!

IceWM installed y default in OpenSUSE.

I just decided to try it, but unexpectedly it became the default window manager (something new in behavior, 4 months ago the system asked before changing the default WM).

Now I cannot logoff from it so I could choose another WM: after logoff the monitor says ‘frequency out of range’ (I wonder, why).

Please give me an advise how me to return to Gnome. Currently writing from IceWM.

hmmm…you probably have elected to have your machine auto-login, and
the problem now is that it will always auto-login to the LAST WM/DE used…

see here, what worked for this trapped person should work for you:

the out of range is a video problem…fixing that is a different thing.