Monolingual, dead apps, shuts down by itself and reformat concerns

Question

Hi, I'm new on Mac, so any advice given to me should be clear and without abbreviation, so I can follow it properly. Thx.
1- I used monolingual without unchecking all the stuff in the two last tabs. The first tab was for the languages, the two last, for the architecture and some other internal components.
2- Since then, my whole Office won't work. I also discovered recently that Toast Titanium and Mac the Ripper would not open either (I did not try them before, thought).
3- Lately, my MacBook would just shut down just after I open it, sometimes 2 times in a row before I can use it. It just happened 5 minutes ago, while I was just surfing on Firefox.
4- When Office was the only symptom, a friend told me to reinstall Office. Now that i have bigger problems, he tells me I should reformat Mac OS. He told me reformatting a Mac is a heavier operation, that as opposed to Windows, it keeps some traces from the older installation, that it is impossible to remove everything, just like if this installation waws the layer on which I a going to reformat and over which the new Mac OS is going to install itself.
I am aware I shoud reformat, even though I did not try to fix the shuts down any other way. I realized that it happens to a lot of user while reading the discussions of some topics. Anyway, my priority concern is the fourth point of my topic. I would still like to know if reformatting is my only way, if there is any other solution.
Thaks in advance, sorry for my bad English, I am francophone.
Regards

Answer 1

You have described two main problems:
1. You used Monolingual in a way that may have removed all the ability to run non-Intel applications, e.g. MS Office.
2. The shutdown problem.
To be sure of fixing the first problem, you can reinstall the OS. There are two choices for reinstalling: erase and install, or archive and install. They are described here:
http://docs.info.apple.com/article.html?artnum=301270
Once you have restored the OS, then you can see which applications do not work, and reinstall them. What your friend said about reinstalling the OS is not correct. If you do an archive and install, you will still have your old files from which you can choose what to keep. If you do an erase and install, none of your old files will remain on your disk.
If you are still having the problem with shutdown, contact Apple.