A key can be invalid for various reasons - Please ensure you have downloaded the correct version of software, if you purchased BullGuard Antivirus your product key won't work with BullGuard Internet Security, if you purchased Kaspersky Internet Security your key won't work with Kaspersky Total Security etc etc.
Need help setting up?
If you need basic assistance we are alway happy to help, we can also set your software for you if you purchase our remote setup package