Larry called in today with a problem of not being able to open IE7 after doing a Windows update with Windows Vista (yet another reason to have Firefox installed on any system). Turns out the problem is with the "phishing filter". Click this link for a solution [1] to the navcancl error in Vista.
Links:
[1] http://itsvista.com/2007/05/kb931768-navcancl-error-crippling-ie7-for-some-vista-users/
[2] https://www.paypal.com/cgi-bin/webscr?cmd=_xclick&business=rick@yourpcpartner.com&item_name=Buy