>>>>>>>>>>>>internet options-->tools-->programs
reset web settings
my addtional suggestion is to install a version that has got rid of tecent explorer.
tecent explorer is really .......
No need resetting all web settings!
Just right below the "Reset web settings" button, there is a checkbox "Internet Explorer should check to see whether it is the default browser." Selete that and close all your IE windows, and reopen IE. You should be prompted for what you want.