If you need to inspect a desktop or laptop for malware (rootkits, trojans & viruses), here's a nice solution directly from Microsoft, and it's FREE.
You can create a bootable CD, USB flash drive or ISO with Windows Defender Offline, which will scan the computer and alert/remove any malware it finds.
It's currently at version 4.1.522.0. Get it straight from Microsoft (32bit and 64bit options):
Note: I've downloaded in ISO format and the actual file size is 319MB, which contained a boot.WIM file with a file size of 202MB.