You can install it by downloading the latest version from the link i posted earlier.
Double click the downloaded .zip file, then double click the SmartPSS installer in the window that pops up.
Or unpack the downloaded .zip file by right-clicking it and select extract all, then open the extracted folder and click the SmartPSS installer.
If SmartPSS is running, close it before installing the new version, otherwise it will say that smartpss or pc-nvr is running.
When the installer starts up, make sure you select both SmartPSS and PC-NVR. I suppose that you could also just select PC-NVR without SmartPSS, but as this is the latest version, i would select both. It will re-install it over the old version.