@doraemon
okay,
boot into a shell (no startup-sequence)
type:
type s:startup-sequence
and start executing the commands line by line printed in the startup-sequence until you strike the one that causes the problem-start with the netinterface one if that is the last one you saw in that previous evaluation
maybe somehow your monitor driver has become corrupt? or the tooltypes in the icon.
very strange that IPrefs works?
perhaps enter startup-sequence and reduce it to just have the bootloader, setpatch, iprefs loadwb and endcli
do you get your proper workbench screen etc?
I wish I was there