GMER is a free rootkit detector and remover utility. It was created (according to other people) by the same author of aswMBR which is another popular antirootkit detector that uses avast! AV engine.
GMER is able to scan your computer and search for hidden processes, services, threads, files, modules, registries, MBR disk sectors, Alternate Data Streams, drivers hooking SSDT, IDT, IRP calls and inline hooks. Although, it is among the best anti-malware tools you should be careful when attempting to delete a hidden service. If possible, attempt to save the log and post it on malware related forums or attempt to send it directly to the author. Furthermore, if you suspect an infection, you can also try aswMBR - a similar software.
Important: The author recommends downloading GMER with a different name to avoid detection by certain malware that might prevent GMER and other security tools from launching. FossHub provides a different EXE name and lists both the regular EXE file and the ZIP archive.