It shouldn't be happening. First of all what is your operating system and service pack?
Also please check your system clock for accuracy, both time and timezone-wise.
Also if you are using any registry cleaners please stop as they can cause this sort of thing.
Rival or similar software could also cause this.
Try uninstalling your product via Control Panel in the normal manner.
Run the MCPR cleanup tool listed inder Useful Links at the top of this page.
Reboot and then reinstall from your online account.