How to remove Sandboxie license and update version on window 7?

Hi to everyone. I have purchased Sandboxie license some days ago and it is running well for everything except web browsing speed while restricting some web sites. I thought it may be due to setting changes so I checked it but failed. The last option was to remove sandboxie license and update the new version. I was surprised when it is not uninstalling. Please give me any suggestion how to solve this problem
