2007 is in the title, but this is more relevant than ever. Windows 8 is really the only OS where Microsoft has started getting scaling for high DPI right (not just text, but layout too), which is too bad given its chilly reception.
Windows 7 is pretty brutal looking on a retina laptop, since your choice is either use their broken DPI scaling, which basically results in really ugly layout, or you can lower the resolution. If you've ever tried running an LCD at a low resolution you know why that's not great. The other thing is that for some reason Apple's bootcamp drivers won't let you run at half resolution where the pixels would at least still be square. (My laptop resolution is 2880x1800, but for some reason I can't scale to 1440x900. I'm not sure if this is just an oversight by apple, or they're just giving windows users the middle finger)
Microsoft isn't really the only entity that should be taken to task though. My impression of GTK and Qt is that they also scale things really poorly. (I haven't tried it in linux, but try running QtCreator demos on a windows 8 machine running at 200% scale.. a lot of them are pretty brutal.)
Why do you even mention Windows 7? It was released in 2009, sure it's not designed to handle retina.
Win8 introduced Metro apps, all work nice with any screen. Legacy software it up to developers to fix, it's not Microsoft's issue. At least major apps, like Adobe CC, Office, browsers support hidpi already.
Things have changed though. The issue of subpixel rendering is gone: MS Office and browsers use Directwrite API, which solves antialiasing, layout inconsistensies, irregular intervals, etc.
Windows 7 is pretty brutal looking on a retina laptop, since your choice is either use their broken DPI scaling, which basically results in really ugly layout, or you can lower the resolution. If you've ever tried running an LCD at a low resolution you know why that's not great. The other thing is that for some reason Apple's bootcamp drivers won't let you run at half resolution where the pixels would at least still be square. (My laptop resolution is 2880x1800, but for some reason I can't scale to 1440x900. I'm not sure if this is just an oversight by apple, or they're just giving windows users the middle finger)
Microsoft isn't really the only entity that should be taken to task though. My impression of GTK and Qt is that they also scale things really poorly. (I haven't tried it in linux, but try running QtCreator demos on a windows 8 machine running at 200% scale.. a lot of them are pretty brutal.)