Well, I tried the repair and windows started telling me to look online for an AV product and to enable windows defender. I rebooted, even though the installer didn't prompt me to. After the reboot, windows was quiet, but the instup.exe process never showed up in task manager. So, i tried to update avast and i got the same result. No need to update, it's up to date (140409-3 is NOT up to date). Also avast tells me that everything is ok, although my defs are 3 days old...
On my destop PC, avast won't update either, it says that 140411-1 is up to date, which isn't.