I've had an ongoing issue with IE not opening my preferred homepage due to uppercase letters in the URL being replaced with lowercase letters which means it won't open properly. I've managed to fix it by doing a clean boot using msconfig.exe and disabling Norton 360 under the 'services' tab. See image below.
If I disable Norton 360 using IE Internet options/Manage Add-ons the homepage will work until I close IE. When it is reopened the problem returns due to the uppercase letters being replaced with lowercase again. The only way I have been able to get it to work has been to disable Norton 360 by doing a clean boot using msconfig.exe.
The image below shows my homepage open and Norton Add-ons disabled.
My homepage URL is http://www.bom.gov.au/products/IDR283.loop.shtml#skip. It is a local weather radar. Note the caps (IDR) in the address. If you replace them with lowercase it won't load properly. See below.
If your having the same problem hopefully this may help.
Cheers.