Move website from IIS 5 to IIS 8.5

Hi,

I have a Web Site running on a Win Server 2003 with IIS 5. Now I have to move it to a Win Server 2012 with IIS 8.5. When I try to browse in the website, it seems like there is some authorization restrictions, because images, jquery scripts and css aren't enabled, it looks like a simple html page. But when the user is logged, everything looks like it should be.

I put web.config files in images/, styles/ and scripts/ folders with the configuration:

<?xml version="1.0"?><configuration><system.web><authorization><allow users="*"/></authorization></system.web></configuration>

but still is not working.

In the Explorer  Console are this messages:

SEC7113: Se omitió CSS debido a un error de coincidencia de tipo MIME 
        (CSS was omitted because of a mismatch of type MIME)
Login.aspx?ReturnUrl=%2fStyles%2fFlick%2fjquery-ui-1.10.4.custom.min.css
SEC7113: Se omitió CSS debido a un error de coincidencia de tipo MIME 
        (CSS was omitted because of a mismatch of type MIME)
Login.aspx?ReturnUrl=%2fStyles%2fCustomStyle.css

and in Chrome, pointing to <link href="Styles/CustomStyle.css" rel="stylesheet" type="text/css" />:

HTTP Error 500.0 – Internal Server Error

HRESULT: 0x80070035

By the way, my website is the only one in this server at the moment, I think that I'm missing some configuration to make everything works fine but I really am clueless with this issue.
Please help! Thanks in advance.