Update: I got another notification, but this time, I checked the programs installed on the PCs on the network. I found the program "Citrus Uptater." I couldn't find anything else, but since that computer is pretty bad for gaming, I think that must be the one. I believe that some virus installed Citris updater as a part of its package since it would not uninstall easily. Anyway, I had to reset the computer. I also installed a paid antivirus for extra security.