whilst trying to upgrade 4OD i keep getting the message ' Error 1720' what is this and how do i fix it.???

try reloading you computer

Did you have a previous version of the power tools on this machine? If so, please uninstall those first.
Are you running as an admin? You must be the admin to uninstall software from the computer.

Try running Windows Defender if that doesn't help, you may have to try using Disc Cleanup in your system tools. click START>All Programs>Accessories>System Tools>Disc Cleanup. If these are not successful in removing Error 1720, then you may have to down load a third party program. A good one can be found at http://fix-windows-errors.com