.asp, "open with" fix

Hello. Hopefuly someone can help!

I right clicked an .asp file and selected "open with"
internet explorer. Then, of course, it went through all of
my .asp pages and changed them to IE icons. I would like
to change them back to the little white windows icon, but
when I go back into "open with" I am unable to
select "unknown application" (which appears to be what
makes the icon be the white windows icon)

What have I done and how can I repair these?

Any help would be appreciated.