The easy way to merge drive c and d in windows, thus enabling dual boot.
You have to delete a partition to be able to add the space to an existing partition (unless you have unallocated space at present), but there are limitations depending upon which partition you want to delete or add to.
1. Right-click Computer > Manage > Storage > Disk Management and look at the graphical display. You can extend a partition using space that is immediately to its right. For example, let’s say you have two partitions showing in the display as C and D. Let’s also assume that C contains Windows and that D is the partition you want to add to C. You will have to delete D, which means the LOSS OF ALL ITS DATA and then add the unallocated space to C.
2. To delete D, right-click its graphic, select Delete Volume and reply Yes. The partition returns to Unallocated for a Primary Partition (or Free Space if it‘s a Logical Drive within an Extended Partition).
3. To extend C using the unallocated space you created in (2) above, right-click C’s graphic and choose Extend.Chkdsk