Problem with my SharePoint site

First i'm sorry for my english.
My problem is with my SharePoint Website running on MOSS 2007 on a Windows Server 2003 with IIS 6.0 ans ASP Net 2.0.
My website was working very well but after some configuration on ISS console i got this issue.
When i try to access to my website with this URL: http://myserver i got an error Message : Content view is not allowed for this virtual directory.
But when i try with this URL http://mywebsite/default.aspx it's working but my CSS and JS file are not loaded. So i get an aspx page without my customisation.
I tried to give all right to my directory wwwroot to different user like thé ASP user, to ISS user ... Without any result.
The strange thing it's :
- when i try to go to my default site which use ASP Net 1.0 it's working well...
- When i try to read my SharePoint list from ACCESS 2007 or directly from the web by the direct URL it's Works
- but when i try to open my website from SharePoint designer it's impossible.

Thanks on avance for any help.