Why can't I make Yahoo my default mail?


Valued Member
I have recently got one new laptop with windows 7 home premium 64 bit and did a clean install of windows 7 home premium 64 bit on my older desktop. Both are using IE 9 for browsers.
Somehow on the laptop I download Yahoo messenger with yahoo tool bar.
With the laptop yahoo mail must be my default mail because if I click on a web page email link it will open my email. Yahoo mail adviser and yahoo mail are installed if I go into unistall programs in the control panel but don't show up under All Programs. I don't care because it works.
The desktop is another story.I downloaded Messenger and have the tool bar but cannot open a email link like the laptop. I cannot down load just the tool bar and check make yahoo my default because it says it is not compatible and to check if I have 32 or 64 bit operating system. Through Yahoo I tried both the 32 and 64 bit tool bar and neither will download. Both give the same compatibility message.
I took my computers to my local Technician and after 3 hrs he could not make it work either.
If Yahoo mail is the default on the laptop why can't I make it work on the desktop? I hope someone has the answer?