There has also been another topic about the same issue created about five years ago, but it didn't solve my problem.
August 6, 2015 Update: Virtual PC 2007 finally functions after I ran it with Windows 7 compatibility mode and as admin.
So, logically, I inserted the VirtualBox Guest Additions CD image into my virtual machine, only to find this error: (VBoxGuestAdditions-x86.exe)
Please refer to your System Event Log for further information."
So I opened the Event Viewer and saw a few errors logs that dated from a few minutes ago. I opened the latest one, and this is what it says:
Event ID: 32
Description:
Syntax error in file "%11"; line 12%; element %13; language %14; processor %15; ver=%16; requestVer=%17; The application failed to launch because of invalid manifest
I'm not really sure if it was the Guest Additions executable that logged this, but it was logged at about the same time I ran the executable. And it was logged as an error, so...
I would really like some help on this issue, as I am preparing this installation for a YouTube video, and no one wants to see some ugly 800x600 16-bit video... Thanks in advance.