Yesterday I were working on a ASP.NET project and needed to add a new Web User Control. I right clicked the project and went to Add New Item. I looked for the Web User Control, but couldn’t find it. I looked again, I asked a co-working, I search for “web” and “user control” and nothing were found.
I then started googling for the problem and found a simple post that told me exactly how to fix this.
Close all your instances of Visual Studio.
Open Visual Studio Command Prompt. 
Type in the following and hit Enter.
devenv /installvstemplates
Wait for this to complete.
When it’s done, open VS2010 again and you should now have all your control templates again.
Happy coding!