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Please try to delete all your partitions and the volume for all of them and you will see them unallocated.
You can format them with Disk management tool.
If the Disk only shows 750 GB on the left you may need to convert it by right clicking on the disk on the left side and select convert to GPT.
The Master Boot cannot detect a 3TB disk.
See if the video at the following link can help you.
NOTE: This link is being offered for your convenience and should not be viewed as an endorsement by Intel of the content, products, or services offered there.