C:\ Boot partition is where Windows is installed. This can also be verified in Start > Computer.
The first partition is the recovery partition for repairing Windows from. I don't actually have
experience in using recovery partitions as I don't buy factory built PC's, but this stays as it is.
You may be able to use the free space by extending the C:\ partition by 35.53GB, but I've
not done this either as I don't want to risk stuffing up my Windows install, and because it is the
Windows partition it may not allow extending the Window partition for the same reason.
Third party software is more flexible than Windows Disk Management and may be a safer way of
extending the C:\ partition, which is a bit small if you keep your music, etc in the default locations.
Another option is to back up everything you have on the M:\ partition to another source and delete it and the other empty primary partition .
Once these partitions have been deleted you can do a quick format and create a single partition
or multiple partitions form the one contiguous space that will result from the deletions.
Again, third party software may be able to use the current free space in M:\ , but with Windows
Disk Management you cannot extend backwards, so to speak. Awkward ain't it ?