What should backup when re-installing Bridge CS3?

I have had big issues of software not working correctly and computer crashing since I got a new state of the art XPS 710 computer last summer. When I loaded Lightroom for the first time last week , it crashed upon opening. (this happend with iview, also, and I have never gottne NikonScand to work on this comutr, also I fially was able to run the scanner with VueScan). Yesteday, after a couple hours with DELL investigating my machine, they told me I had to reinstall the operating system. Not fun, but they will tlalk me through it. I have documents and images all backed up on an external hardrive, but I need to know what to back up from Brdige so that when I reinstalll it my huge hierarchical list of keywords will get reinstalled. John did tell me a few weeks ago how to export the keyword file and then import it into Lightroom -- however, I never go that far because Lightroom crashed. Perhaps I jsust export and then import that same file. I MUST be sure of that though before I attempt this major fix on my computer.

Also, is there anything else that I need to back up and then reinstall to get Bridge and Photoshop CS3 working the same as they were (or rather, better than they were!)

And then this leads me to the question of future routine backing up of the keyword list in case I get a harddrive crash. The keyword file is not being backed up at all. My documents and images back up every night onto the external hardrive, but it only occured to me now that I ought to be backing up this other stuff, and I haven't a clue how to set that up.

Many thanks!!

Susan