If your unable to change your homepage in the usual way then follow the instructions below to resolve the problem.
Warning: Always backup the registry before making changes!
Start>> Run>> regedit
HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
Search for "Start Page"
Search for "Search Page"
Rename as necessary
HKEY_LOCAL_MACHINE\Software\Microsoft\Internet Explorer\Main
Search for "Start Page"
Search for "Home Page"
Rename as necessary
On a fresh installation, Internet Explorer sometimes defaults to MSN as homepage
for first 2/3 bootings. This can be resolved from here:
HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
Search for "Default_Page_URL"
Above registry keys also useful for sites forcing homepage.