This is really off topic.

I'm having an issue opening XAML files in Visual Studio 2010. The IDE simply crashes. I have opened a bug with Microsoft regarding that matter and will update once I have some sort of a result.

Anyway, I thought it might be something I've installed in the past few days, so I went to System Restore – which of course, happened to be disabled… So, I thought to myself, I'll simply enable it, so that it won't happen again. That wasn't simple as I thought though. When trying to enable system restore on drive C it gave me an error "There was an unexpected error: The filename, directory name or volume label syntax is incorrect. (0x8007007B). System Restore will now close."
After some investigations, I have discovered that I happen to have two instances of C drive on the System Restore Properties form. One appeared in the beginning and the other at the end and was called "C (missing)" – which, by the way, is not a good sign.
All I had to do is to turn off system restore for that "missing" hard drive – which made it disappear, and enable system restore on the correct C drive.