Is it just not possible? I can make a new partition and add to the the other existing partition but for some reason I can't add it to the one that I want? The option to extend is greyed out.
when you remove the 300, does it make the 300 into an extended partition?
If it does, you need to delete the extended partition and then c should let you expand it.
Try Easeus Partition Master. It's free and works when the Windows Disk Management doesn't. As always, be sure to make backups before doing things like this. You probably won't need it, but we know how Murphy loves computers, so the ounce of prevention is well worth it.
when you remove the 300, does it make the 300 into an extended partition?
If it does, you need to delete the extended partition and then c should let you expand it.
check the crossed out answer - not sure whats wrong with it: https://social.technet.microsoft.com/Forums/windows/en-US/dba8d18d-9f9c-44c3-8bb1-76cde3455024/i-cant-extend-my-c-drive-even-tho-there-is-free-space?forum=w7itproperf
It goes into unallocated, but I still can't do anything.
Try Easeus Partition Master. It's free and works when the Windows Disk Management doesn't. As always, be sure to make backups before doing things like this. You probably won't need it, but we know how Murphy loves computers, so the ounce of prevention is well worth it.
Good luck.
I'll give it a shot then since other options are unavailable.