You are encountering one of the following issues under Outlook:
Nothing happens when clicking on hyperlinks.
Clicking on the links will open the browser, without loading the webpage.
Several solutions are available:
The simplest solution is to configure Internet Explorer as the default browser.
Open "Internet Explorer", click on "Tools" then "Internet Options."
Go to the "Programs" tab, verify that Internet Explorer is the default Web browser.
Click on "Make default" then apply.
It is also possible to configure this option from the Control Panel.
Open "Add/Remove Programs", click the "Set Program Access and Defaults".
Go to the "Custom" tab, select the "Internet Explorer" browser, confirm with OK.
The trouble opening links may also be due to incorrect values of the "urlmon.dll" file
Close any running programs.
Click on Start > Run
Type "RegSvr32 urlmon.dll" and then click OK.
The following message shall be displayed: ""DllRegisterServer in urlmon.dll succeeded"
Restart the computer and check the functionality of links.
If the problem still persists, you need to repeat the operation using the following commands:
Internet Explorer 7
Open Internet Explorer, click on Tools then Internet Options.
In the "Advanced" tab, click "Reset".
Apply and restart the computer.
Internet Explorer 6
Here is a free utility called "Power IE6" designed for troubleshooting, repair and optimize Internet Explorer 6. Power IE6 can be used with Internet Explorer 7 too.