To uninstall Internet Explorer 8, follow these steps:
Carefully select and then copy the following command:
%windir%\ie8\spuninst\spuninst.exe
Click Start, and then click Run.
In the Open box, type Cmd.exe, and then press ENTER.
Right-click inside the Cmd.exe window, and then click Paste to paste the command that you copied in step 1.
Press ENTER to uninstall Internet Explorer 8.
When the uninstall program is finished, restart your computer.
After a reboot, download and install IE7 from the MS website. (Uninstalling IE8 will leave you with IE6 initially)