No, virus scans are not designed to help speed up your PC. They are designed to detect and remove malicious programs from your PC. While they may find certain types of unnecessary programs that can slow down your PC, they are not intended to provide any sort of overall performance boost. If you want to improve the performance of your PC, you should first try running a disk cleanup, deleting any temporary files, or uninstalling unnecessary programs. You can also make sure that your PC is running the latest updates, as outdated software may impact performance.