How do I migrate to ASP.NET without losing PR

[musicales]

This may seem like a question for the .NET forum, but I think Googlers may be more able to answer - is there any way I can move to ASP.NET and not lose the particular page (with all it's links in Google) eg when page1.asp becomes page1.aspx is that treated as a new page, or the same.
If so, isn't it pretty much like starting from scratch as far as the SE indexing is concerned?

[ciml]

From a Google point of view, you should want to keep all URLs that are linked from pages outwith your control. Over time, the addressess that are linked only from within your site should get the PageRank that used to go to the old addresses.

You should ensure that people hitting the old addresses for a month or two get helpful 404 pages or HTTP redirects to the new addresses.

Do you really need to change your URLs to use .NET? This seems a rather odd way to do things, it may be worth bringing that up in the .NET forum.

Cool URIs don't change [w3.org]

[Torben Lundsgaard]

As I understand ASP.net files are named .aspx because they are not parsed in the same way as .asp files. However, if you are 100% sure that you only will be using ASP.net you could set up the server so .asp files are parsed as ASP.net