Yesterday I was running into a problem with Visual Studio 2010 and SilverLight 4. I asked for help internally. There was some suspician that this history might have something to do with my problem, but I had installed all kinds of tools on my machine over the last couple of weeks. Visual Studio 2008, 2010, Silverlight, Silverlight for Phone, etc. So I was grilled on when I installed what, and what order etc. I had no idea.

So I ask my friend Pat. He mentioned Reliability Monitor. So I type Windows key, "reliability", I select "View Reliability History" and I got this:

 

The nice thing is that it gives you a full history what went wrong, but also what is installed and when on the machine. You can even export an xml file and send it over or ask for it. This might come in handy when your mon/dad/aunt/neighbor claims that her/his machine magically became very sluggish without any user interaction.