Being an experienced Word user, I'm pretty sure there is no way to disable automatic document recovery. Word has a feature called autosave that saves a copy of the current document to a temporary file every X minutes (you can tell Word what X is; it defaults to 10 minutes). If Word crashes or becomes non-responsive, this file will be presented as a recovered file the next time you open Word. You can, I suppose, set X to something like 600 minutes, so that Word never writes a recovery file. To do this, use the Tools/Options/Save menu.
Since you also say that Word sometimes won't start due to memory problems, I suspect that the files it wants to recover are the ones you tried to open. If that is the case, then Word generates an autorecover file when it starts up, before it tries to display the document. And if this is true, then my suggestion to set X to a high value is useless, since the recovery file is generated as soon as you open a file.
The basic issue, then, is fixing your system so that there are no memory problems. Since this appears to be an intermitent problem, my guess is that the Word program is corrupted, or possibly the operating system itself.
I've experienced the display memory problem myself, though not for 10 years or so. As I recall, I had to remove and reinstall Word, and possibly also Windows.
Hopefully someone else will have more helpful answers.