Antivirus companies provides some free tools designed to remove specific malware or popular viruses. One of these tools is Avira AntiVir Removal Tool that will scan and fix a list with dangerous threats.
Instead reinstalling entire operating system you could try a removal tool, especially if you know what virus family has infected your computer.
This program is portable and doesn’t need installation, just run it from an USB or from local drive.
Will scan memory and all computer’s files, will save a log and will display a report with scanned, infected and repaired files.