Thank you for the explanation, Charles. I am in such a newbie state yet that I hardly know how to work with one instance of VS <g>. In fact, just within last 30 minutes I opened and closed VS 2012 about 10 times. Each time I created a project or a site and then realized that that was not what I wanted. So I remove, delete, start over <g>.

>I think that what both Craig and I are talking about is running 3 VS IDEs at the same time. ( I might want to refer to another project while working on a project for example.) I find VS2012 seems to have less problem with that than VS2010. I have also had VS2010 and 2 VS2012 spread out on the screen at the same time.
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>I biggest problem I find is if you forget you have a second IDE open, decide to update your extensions or change something in your settings, then close the changed IDE, then later close the unchanged one. They still are the same program and share configs that sometimes automatically save state on close.
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>I think Craig is correct that doing multiple VS IDEs open at the same time carelessly can cause a break in the fundamental warp of matter in the universe and may result in a black hole.
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>>Sorry for a newbie question. Does it mean (your statement of 3 instances of VS) that, just like SQL Server, you can have the same VS (e.g. 2012) installed as 3 instances? I am curious if yes and why would someone need that.
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>>>3 instances of VS is asking for trouble. Likely to cause the universe to explode. Also keep in mind that 64 bit OS uses more memory than 32 bit OS.
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>>>>I know that but VS that can use 8gb is going to be a lot faster than VS using 3 - especially if you have 2 or 3 VS open.