FS.exe is a dangerous executable, which belongs to Windows System Defender. This file should never be kept on your computer because there are lots of malicious activities that can be initiated by it. The primary purpose of this executable file is to start a parasite or launch some of its components. Once executed, Windows System Defender starts activity which is was created for. Beware that you should never trust its scanners or pop-up ads because they seek only to trick people into purchasing the fake removal tool. Before that, Windows System Defender reports about hundreds of different viruses and then says that the only tool that is capable of removing them is its licensed version. In reality, it is just a trick used for swindling people's money. If you don't want to lose it, you should remove FS.exe file and related rogue anti-spyware. Keep in mind that FS.exe is a significant part of a dangerous threat, but it can also work on its own, so you should never leave this file on your computer. For eliminating it from the system, you should run a full system scan with Reimage.
Please, don't waste your time after discovering FS.exe on your computer because there are lots of troubles that can be initiated by this virus. For that you should not only terminate this executable file because this won't remove related malware. For that you should run a full system scan with your anti-spyware.