After a evening trying to fix my computers here is the status in between:
A normal Arch update on my old laptop made it recognice wifi passwords again so that one is working fine now.
On my new laptop I found out that by installing windows I had to create a special partition for EFI into which I copied my kernel. After a Arch update which gave me a new kernel but saved it into the old /boot partition nothing worked. I copied the kernel manually into the EFI partition and everything works again. Now I am mounting the EFI partition as my /boot so next time the updater can hopefully update the files in the right place.
I hadn't have the time to check why windows doesn't see WiFI and ethernet, and I hadn't have the time to check what's wrong with my work laptop yet, but I have my big desktop at work and this is just a backup if I need to work somewhere else or want to workk from home, which rarelly happens.