I am trying to shrink my partition by 20gb to make room for ubuntu, but whenever I open disk drive management and try to shrink it, it allows me to specify the amount, but the "shrink" button does not become active. I cannot click on it for some reason. Anyone know what the problem might be?
Can you post a screenshot of your Disk management window?
What do you mean you have 20 GB of unallocated space in your C: drive?
Do you mean that the 20 GB of unallocated space is now on your hard drive?
If that is what you mean then when you install ubuntu use the manual partition method when asked to
specify where to install.
You can use the disk management tool to create a NTFS partition with the unallocated space.
Ubuntu will reformat it during install to the ext3 file system needed for Linux.
You should create an NTFS partition of about 18 GB from the unallocated space because you will need about 2 GB for a linux swap partition.
The install routine's partitioner can create the 2 GB swap partition from the remaining unallocated space.
Don't worry that Ubuntu will be installed on a smaller space than you anticipated, 18 GB is plenty big enough.
Please post that screenshot.
Below is a link to some very good info on dual booting Ubuntu with Windows.