ok, I believe through all these installs Frans, the hard drive or registry has become corrupt, and this is the cause for your problems.
I would like you to do the following please as we are going to do a clean install of Office.
First, go to www.revouninstaller.com
Download the 30 day trial (we only need this) and install it.
run it and use this to uninstall office.
Once uninstalled, restart the computer
than do the following please
Download CC Cleaner (free) from hereCC Cleaner
(Click Download Latest Version on the top right)
Run it and let it scan and repair your registry.
Once done, restart the computer
Press the windows key + X and choose Command Prompt (admin)
A black window will open.
Type in it
press enter and when it has completed, type in
It will give a message "the type of the file system is NTFS cannot lock current drive.
chkdsk cannot run because the volume is in use by another process. Would you like to schedule this volume to be checked the next time the system restarts y/n" Say Y, press enter and restart the computer.
Than install Office again. This will be a clean install and it should then install correctly.
Once done, test if the programs now open correctly and tell me if they still give you the errors please.