System Data Delete access rights

Good morning,
I tried late into the night, browsed through forums, but did not succeed.
The problem:
Yesterday I seemingly smoked the GPU of my MacbookPro Late 2008.
Bootloop, but otherwise no graphic features.
All kinds of resets up to the new game installation did not work.
Now I'm in safe mode (he has bid, probably because he boots without the Graka) and would like to disable the graphics driver for a guide.
These are indeed in the
system - Library - Extensions
copying is natural, but delete from this folder does not work.
I press "alt + cmd + backspace"
Delete Yes
Admin password
Then the message "I do not have the correct access rights". Сhange access rights in information or add users to information in the folder or in the parent folders also does not refer to the necessary access rights.
10.11.6 so barricades its system files that I'm stuck here. The assumption that the Graka is over seems to be confirmed, if I can start in Safe Mode, but for that I would have to deactivate the Graka driver. I am now only able to expand the hard drive and my iMac to delete the necessary files. Someone else without other ideas? Must be possible to adjust the access rights.
Thanks in advance,