Run this command through command prompt.

C:\Windows\Microsoft.NET\Framework\v2.0.50727\aspnet_regiis.exe -i


http://msdn.microsoft.com/en-us/library/k6h9cz8h.aspx
http://kbase.gfi.com/showarticle.asp?id=KBID002202
http://www.devx.com/vb2themax/Tip/18849