I don't know what I have done, but my virtual Windows Vista machine seems to be scaling down the resolution of everything just a little bit. I only notice it when I try to read text that is being display graphically (i.e. things look fine in NotePad but not in WordPad). The best explanation is probably the picture below. This box had been working fine for a few months. I've apparently done something to it, but I don't know what. I've never used scaled mode, which was my first suspicion. I have uninstalled and re-installed guest additions on the box. I run it at 1280x960x32, although I have verified that the problem happens at any resolution. I updated to the new VirtualBox release this week, but nothing changed.
I also have a Windows XP box which does not have this problem, but I need to have a Windows OS that hasn't already reached the end of its support life. I hesitate to make a new Vista machine as I had to call Microsoft to activate the OS when I originally made this machine.
I would appreciate any and all ideas as to the nature of my problem. Thank you!

