Here's an update on this problem. I just found that there is a new version of the Microsoft Intellipoint drivers - version 6.3. So I installed it and the problem with menus disappearing seems to have gone. But the white screen during defensive fire was still there. I read somewhere that some problems are caused by the wheel button being assigned to 'Instant Viewer'. I think with this feature active it takes snapshots all the time and this can interfere with your programs. So I re-assigned that button to something else and so far I haven't had the white screen after playing a couple of turns of games in the ACW and PzC series. Hopefully the problems are gone...
[url="http://homepage.ntlworld.com/a.r.barlow/acwgc/acwgc_personal_record.htm"]General Antony Barlow[/url]
[url="http://homepage.ntlworld.com/a.r.barlow/acwgc/western_theater.htm"]Commander, Western Theater, Union Army[/url]