With the use of computers, many people have started to prefer green software because it brings a lot of convenience, such as one-time installation, no junk files generated, and no need to reinstall a bunch of software after reinstallation of the system, etc. However, due to the rampant viruses, there are certain risks associated with using green software. If the system gets infected, reinstalling the system and then reinstalling the corresponding software can help avoid viruses to some extent. But since green software doesn't require reinstallation, if you use green software that has been infected by a virus, your system will still get infected, regardless of whether your system is clean or not. Moreover, the number of viruses that modify .exe files is increasing, and they are becoming more rampant. The infamous "Panda Burning Incense" virus from a while back falls into this category.
Therefore, performing an MD5 checksum for green software and regularly re-verifying the MD5 can help reduce the likelihood of being infected and having the virus reside long-term on your computer. However, manually performing an MD5 check on each piece of software is a very labor-intensive task, and re-verifying is also quite troublesome.
Now, someone has created a tool for us: AccuHash. Its homepage is here http://www.accuhash.com/. This software was developed by Russians and can generate an MD5 checksum for all files in a specified folder, which can later be re-verified quickly. Additionally, you can specify MD5 recording and verification for certain file extensions, making it convenient to exclude unnecessary files like .txt files from the process.