ASP.NET - Related to vs-2008: My vs-2008 getting problem. it code behind page in desable mode.

hi,

my vs-2008 getting problem. it disable the code behind. toolbox controls not appear and im not found source code,desing tabs ,*aspx.cs  work fine.

what happened to my vs-2008. how i can solve this problem.

please suggest me thanks in advance.