Normal.dot is the default document template of Word. If you are having problems with it, delete it. But do a search for it, as there can be multiple copies. Word is funny that way, and viruses also make corrupt copies. Find them all, and delete them all. Word looks for normal.dot to run. It will not run without it. Therefore if it does not find one, it will make one.
It is, as you note, a global template. Which means it, and everything in it, is available in all instances of Word. This is why you should not put macros, and autotext, or anything that you really want to keep, in normal.dot. You should always create a personal global template to store your macros and other stuff. Normal.dot DOES get corrupted and have to be replaced with a clean copy. Once corrupted, it rarely can be fixed. You have to delete it and start Word with a new copy. If you have macros etc. in another global template (and be sure to make backups), then if you need to dump normal.dot - you do not lose your work.
Gerry