I have been using Avast antivirus, and it has worked fine with Windows Mail for a long time. I also tried disabling Avast, but it did not help. I also tried disabling the firewall (PC Tools), which did not help.
As I explained, when I try to open Windows Mail, I get the error window WinMail.exe, "0x8007000e", and the program won't open.
I tried adding the registry key a few times (from this site), but it still will not show up in the "default programs", or rebuild any files. Very strange. I wish it were not part of the OS, so I could just reinstall, but, I guess that would be too easy!
I just yesterday installed Mozilla Thunderbird, so I would have a working email program, but I had this problem days before installing Thunderbird.
Any ideas would be appreciated!