To disable or enable the registration reminder you may set the following
keys (WARP 4 only!) :  File     OS2.INI
Application  PM_Workplace:ART
Key      DISABLED
Value     fully qualified name
       of ARTCHRON.EXE with
       a trailing null byte
Description  If this key is set, the
       registration reminder is
       disabled
Created    ?
Deleted    ?
Example    "C:\OS2\ART\ARTCHRON.EXE"
 File     OS2.INI
Application  PM_Workplace:ART
Key      ENABLED
Value     fully qualified name
       of ARTCHRON.EXE with
       a trailing null byte
Description  If this key is set, the
       registration reminder is
       enabled
Created    ?
Deleted    ?
Example    "C:\OS2\ART\ARTCHRON.EXE"
Source: Ralf Ulrich (see EMail Addresses)
Note: You can also delete the two keys to fully disable the registration reminder. Or use the Install Object - Inventory in the new folder "C:\OS2\INSTALL\Installed Features" (where C: is your boot drive) to uninstall it completely.
Double-Click on to open the parent folder of the "Install Object - Inventory" folder right now.