problem during opening design mode of .net 2005

[pintu]

Hi dear friends..

I hav a problem while using .net 2005..am working in asp.net 2.0. Now
the problem is that i am unable to open the design mode of any .aspx
page. i am only able to access the code behind and the source
view(html mode) of that page...Again while working on that page's
source view am unable to delete anything by either using delete or
backspace key..So wht might be the problem plz let me know.and also
the possible solutions for that..should i reinstall the .net framework
or there is really some solutions that..plz let me know as soon as
possible..


Regards
Priyabrata