You cannot format the "C:" drive (or whichever partition contains your active Windows installation) while Windows is running. To wipe your main drive, you must use a Windows Installation Media . Method 1: Using File Explorer (Easiest)
If you want to wipe a drive completely—removing all partitions so it becomes one single block of storage—Disk Management allows you to do this: format a hard drive windows 10
After initiating the format, a warning will appear, stating that all data on the drive will be lost. Once confirmed, the process begins. For a large multi-terabyte drive, a full format can take several hours. Upon completion, the drive will appear empty, with a fresh file system ready to store new data. It is important to note that formatting a drive is not the same as "shredding" or securely erasing it. A quick format, in particular, only removes the addresses of the files, not the files themselves. For anyone planning to donate or dispose of an old drive, a full format is a minimum step, but using dedicated disk-wiping software that overwrites all data multiple times is recommended for truly sensitive information. You cannot format the "C:" drive (or whichever