more than likely you can reinstall direct x and it will be fine.
in the future to try and help with issues like this, you can partition a smaller area to just the os.
i personally have a 128gb ssd for just my os, and two 512gb ssd's in raid 0 for all of my files.
you can do the same with one drive and a partition manager. take a 1tb drive and set aside 128gb when you install windows. you can do this with the windows partition manager during install.
Partition Manager before Install
with this handy tool you can make physical limitations on the drive so you don't have to buy additional drives.
if you can move your files off of the windows disk, so you can do a reinstall.
while you are doing a reinstall, use this tool to keep the os seperate from your files.
that way you can reinstall your os any time there is issues. since windows is about as reliable as bubble gum holding down a weld joint.