I was having a problem with Visual Studio Locking up after doing an upgrade from 2.0 to 3.5. The upgrade happened when I opened a new kentico 5.0 install that one developer had been working with through the CMS desk only. He installed as a .net 2.0 app with the Kentico Web Installer.
When I opened the Solution file with VS 2008, it asked me if I wanted to upgrade the solution to .net 3.5. I said yes. From that point on, VS would load fine, but the moment I tried to open a .ascx file or .cs code behind, it would hang indefinitely.
After removing and re-adding the website project to see if that helps, I decided to try with a fresh solution. That didn’t help either. After doing a manual compare of the Solution files in notepad, I found one difference in the project definition node.
Microsoft Visual Studio Solution File, Format Version 10.00
# Visual Studio 2008
Project("{E24C65DC-7377-472B-9ABA-BC803B73C61A}") = "MyWeb", ".", "{420F4FED-2F28-4BE5-8CEA-9A6B9A57558B}"
ProjectSection(WebsiteProperties) = preProject
TargetFramework = "3.5"
Debug.AspNetCompiler.VirtualPath = "/"
Debug.AspNetCompiler.PhysicalPath = "..\Project\MyWeb\"
The TargetFramework property is in the default WebProject.Sln that the Kentico web installer generates. Both my new Solution File and the Original Solution file that Visual Studio “upgraded” did not contain this property. After I added that property back to my new solution file, everything loaded fine. I’m still not sure what caused the hangs, but this seems to fix it.
FYI, I hope this helps.