An assistant for changing this keyboard shortcut can be found in the on-line Mac OS Help within the "Files and Programs" chapter, under "Switching between open programs."
If you have experienced other issues since installing Mac OS 8.5 please read the About Mac OS 8.5 Read Me and Installing Mac OS 8.5 Read Me that come with Mac OS 8.5.
This information is from the Tech Info Library Article 58129: "
Mac OS 8.5: About Mac 0S 8.5 Read Me".
Tech Info Library Article 17159: "Locating Vendor Information" can help you search for a particular vendor's address and phone number.