My RDP error per se was fixed by the method outlined above.

Now, I just have the occasional (sometimes very occasional, like 3 times in a row!) winlogon.exe error, but ONLY as administrator. After I deleted the administrator’s profile, and WinXP created a fresh profile, it worked fine for several days…until it didn’t! At this point, it seems like a 50:50 chance every time I log in as administrator (e.g., to do a system security update) whether it will crash. It’s also irreproducible as to timing: sometimes the crash is just after logging in, sometimes several minutes after logging in, and sometimes even as the (administrator only!) password is being typed (this last one is really strange, I admit, but it has happened two or three times!). BUT, as far as RDP goes, this winlogon issue is not connected (AFAI can tell): it happens occasionally during direct connection logins as well.