Google playstore returns error "couldn't intall" or "could'nt update" for several apps

I did all the steps mentioned on the forums; cleared cache, and data, uninstalled updates  to play store etc.. Nothing seems to work. These are mainstream apps including Google, google chrome: fast and secure and severfal other mainstream apps.

Some apps do install or update.

I can find no error code which would explain the error.

I have 60 gig storage available, a super fast broadband connection and no other problems. 

Other devices at home belonging to my wife and myself work properly.

Any advice most appreciated