Is it InDesign only, or can you type in other kinds of documents? It sounds like a bad keyboard, or, if wireless, you need to replace your battery.
It's not a wireless keyboard & it's only Indesign I cannot type in.
I can still type on Photoshop & Illustrator CS6. It's so odd I have no idea what to do
When you say you "downloaded" CS6, where did you download it from? If you copied or migrated it from another computer, that will not work. Not all the files would be properly copied by those methods.
I purchased the CS6 Creative suite online from adobe.com - and downloaded from there
all the other programmes seem to be working fine only InDesign is not working
Can you try rebooting the system in safe boot & check if you are able to use the keyboard shortcuts?
I rebooted the system in safe and it seems to have fixed itself, the keyboard shortcuts and all type is now working.