Compilation Error or Web.config File is Missing - ReflectedSchemas

Recently while writing a program for a friend using Visual Studio 10 Express, all my web pages had the following error on each control:

Element '[control type]' is not a known element. This can occur if there is a compilation error in the web site, or the web.config file is missing

I found that if you delete the files from the following folder, it should solve your problem:
C:\Users\JoshuaYockey\AppData\Roaming\Microsoft\Visual Studio\10.0\ReflectedSchemas
or if you are using Express:
C:\Users\JoshuaYockey\AppData\Roaming\Microsoft\VWDExpress\10.0\ReflectedSchemas

Hope this helps others.