You can by placing a short cut in the windows startup folder, just like any other windows program. However if you do you are likely to encounter problems as downloading mail while the anti virus is still loading and the network is busy announcing your machines arrival to the network ( which might be a network of one) and any of a dozen other program are loading is fraught with risk of timeouts and server disconnections as well as error messages that make little sense because they are about something that is still loading. So the bottom line is sure you can, but if there are issues take it back out of there as a first step.