Internet, Networking, & Security Antivirus PC Tools' Alternate Operating System Scanner Review Use AOSS to scan for viruses before Windows starts Share Pin Email Print Antivirus Browsers Cloud Services Error Messages Home Networking 5G Antivirus VPN Web Development Around the Web View More By Tim Fisher General Manager, VP, Lifewire.com Tim Fisher has 30+ years' professional technology support experience. He writes troubleshooting content and is the General Manager of Lifewire. our editorial process Facebook Twitter LinkedIn Tim Fisher Updated January 03, 2020 PC Tools' Alternate Operating System Suite (AOSS) is a software suite for Windows that functions not only as a free bootable antivirus program but also a file recovery and data destruction program. The menus are easy to navigate through and you can start a virus scan in just a few moments after booting into AOSS. What We Like Has a graphical user interface. Easy to work with. No custom settings (scans are easy to start). Includes other useful free tools. What We Don't Like Built for the Windows OS only. No custom settings (not very advanced). Over 350 MB download size. Download Alternate Operating System Scanner PC Tools is no longer available. As such, you can not browse for the AOSS download on their website and no more updates will be released. The link above is an archive of the last released version, v2.0.5, which was released on December 9, 2010. Installing Alternate Operating System Scanner This bootable AV program is available as an ISO file called AOSS.iso. After downloading it from the link above, you have to burn the Alternate Operating System Scanner program to a disc. Then, you can boot to it before Windows starts up. Thoughts on Alternate Operating System Scanner Because Alternate Operating System Scanner doesn't have any scan options or other custom settings, you can begin a scan fairly quickly once you've booted to the disc. On that note, if you're looking for a program that lets you perform particular scans like checking certain folders only, you won't find it with AOSS. I still like Alternate Operating System Scanner even though it doesn't have custom options because the program is really easy to use. Unlike some other bootable antivirus programs, AOSS lets you use your mouse to control the menus, which makes it very simple to use. Just choose Anti-Virus scanner from the AOSS main menu and then select the partitions you want checked to immediately begin a scan. Also from the main menu are some additional tools, such as a system shell and file manager that lets you compress, remove, and copy data.