"Defragment and Optimize Drives" is a built-in tool in the Windows operating system that helps improve the performance of your computer's hard drive. Over time, files can become fragmented, meaning they are stored in non-contiguous spaces on the disk. This can slow down access times as the system has to work harder to find and read these scattered pieces. The tool reorganizes the data on your drive, placing related files closer together. This process can lead to faster file access and overall improved system performance. Regularly using this tool can help maintain your computer's efficiency, especially for traditional HDDs that benefit from defragmentation.