Thanks for the quick reply, Shane.
I had run the file permissions repair as a part of the firewall fix (checked "reset registry permissions," "reset file permissions," "repair WMI," "Windows Firewall," and "restart when finished." I do already have 7-Zip installed and, in fact, the dialog box with the error message reported below had 7-Zip in its title bar. When right-clicking on the exe file, however, there was no ability to extract. Poking around last night, I thought I'd check the file permissions and found that UAC was turned off for some reason. Not sure why, but as soon as I turned that back on and rebooted, I was able to install the HP software.
A second similar problem, however, has arisen. I have a couple of other installation files that I know recently worked fine -- a FileZilla update is one of them. Attempting to run that, and a couple of others, produces a dialog box with "NSIS Error" in the title bar and the message "Error writing temporary file. Make sure your temp file is valid." This, too, is something brand new. Any ideas on this?
Thanks!
Susan