VS2005 and VS2008 .sln file icon incorrect

I had installed VS2005 and VS2008 on Vista Business, both work fine. But today, I found .sln file icon losted and cannot open it with double-click. So I associate .sln with Visual Studio Version Selector, it works again, but the file icon is incorret.

I spent all the afternoon to make a ton of mistakes, the final solution is: associate .sln with <osroot>\Program Files\Common Files\microsoft shared\MSEnv\VSLauncher.exe.

The headache had been resolved, but I cannot find the reality. The conclusion is more bigger and more danger.