Rewrite of existing web site.

New programming language may effect SE positions

[dodger]

I may decide to rewrite an existing very popular web site because over the years it's been added onto and has problems that are associated with that type of ad-on growth.
The site is very well indexed everywhere.
The site is .asp and I'm told I should rewrite in .NET but if I do I'll have massive problems with the SE's.
Any suggestions?
Do the rewrite in .asp?

[sharbel]

Are you talking about the potential problem of the .aspx extensions as opposed to the .asp extensions? If so, on your server you can set .asp extensions to be handled by the ASP.NET framework, as well as .aspx pages.. That way you can keep your pagenames the same, if you wish.

[dodger]

Yes the extensions, everything would be new, thanks for the suggestion.