When you have a storage device (such as a USB key, an SD card, or a hard drive) that has several partitions, formatting it so that it can only have one main partition isn't always easy. This will show you how to format it on windows so that it can be as good as new.
Step 1: Open Command Prompt
Press simultaneously the windows key and the R key, and the "Run" window will appear. In it, type cmd. This will open up command prompt, which will be used to format your storage device.
Step 2: Open DiskPart
In the command prompt, type diskpart. If a window pops up asking you to grant administrator access, click yes. Diskpart is used to add partitions to storage devices, remove partitions, assign letters, and more. If you want to read more about it, click here.
Step 3: View All Storage Devices Connected
To prevent things from going terribly wrong, remove as many storage devices (except the one you are trying to format) from your computer. Then in command prompt, type list disk. This will show you a list of storage devices connected to your computer.
Step 4: Select Your Storage Device
In the list diskpart shows you, find the storage device you want to format. Look at the size of the volume. For example, if you are formatting an 8GB SD card, look for a volume around that size. In my case, 0 is my internal hard disk, and 1 is my 8GB SD card. Once you have found which number represents your storage device, type select disk #, # representing the number of your device.
Step 5: Remove All Partitions
Now, type clean. This will clear the partition table.
Step 6: Create a Main Partition
Now, you must create a partition to make your storage device usable. To do so, type create partition primary.
Step 7: Format It
To avoid file corruption, format it. Just type format fs=fat32 quick. Your storage device is ready! Just close command prompt and you're ready to go.