You cannot disable the back button directly. Here is an article that discusses options for achieving the same results. The article focuses on ASP, but it can be translated to other server side languages:
You can either use a link with a _blank target or use window.open to get a new instance of IE. Is that what you mean?
<a href="newinstance.htm" target="_blank">Click here</a>
<a href="newinstance.htm" onclick="window.open(this.href, '_blank'); return false;">Click here</a>