I beleive if you install .net framework 2.0, asp.net 1.x won't be installed. But if you're wondering if you can run them side by side, then the answer is yes, you can. If .net 1.x was installed and then you install .net 2.0 then they both will be there. If you install 2.0 and 1.x was not there then asp.net 1.x won't be installed. You can double check this by going to IIS, right click on the default website. There should be an ASP.NET tab, under that tab there's a dropdown (ASP.NET version) and you have 2 values: 1.x or 2.0. That is how I have it because I have both versions. I'm not sure if the tab will be there if you only have 2.0 installed.
JoNaS
MVP - Microsoft Most Valuable Professional
MCAD - Microsoft Certified Application Developer
http://www.jstawski.com