You didn't check what version of Internet Explorer you are using. Open it (Start/All Programs/Internet Explorer) and go to Help/About.
If it is IE6 got to Tools/Internet Options/Security and set all zones to default then click Apply and OK. Go to the Content tab and make sure Content Advisor is off. Go to the Advanced tab and make that default, Apply and OK again.
If it's IE7 or IE8 go to the Advanced tab and click Reset, Apply and OK. Close and reopen IE. Go to Tools/manage Add-ons and re-enable them all.
Then try a complete cleanup and reinstall.
1. Uninstall all McAfee programs through "Add or Remove Programs" in Windows "Control Panel".
2. Use the MCPR tool, see this article: How to remove supported McAfee consumer products using the McAfee Consumer Products Removal tool (MC...
This will remove all McAfee remnants from your computer. (you must have Windows Vista, XP or 2000 SP4 to use this tool)
3. Launch Windows Explorer and delete all McAfee files in "Program Files" but especially in "C:\Document and Settings\<user>\Application Data" and "C:\Document and Settings\All Users\Application Data". You have to set Windows Explorer to show all hidden files and folders (Tools > Folder Options > View tab). Just delete the McAfee folders even if they are empty in all the "Application Data" folders. Can be more than one!
In Vista: C:\Program Files, C:\ProgramData and C:\Users\yourname\AppData\Roaming
If you can't find these files don't worry. It just means that MCPR has done its job.
4. Reboot and redownload/reinstall your McAfee products directly from your account at the McAfee web site or your ISP.