How would I go about doing this without reformating?
If you get a firmware update from WD's website it probably comes in .exe form so you can just launch that and it will update everything automatically.
If not - there's two things you can try.
1. Go into Windows Explorer in safe mode.
2. Right click "my computer".
3. Click on "Manage".
4. In disk management mode, right click the primary disk and click on "properties".
5. In the properties dialog click tab "Tools" then "Check drive for errors". That should launch a tool that will find the defective driver and replace it.
Alternately try this:
1. Go into Windows Explorer in safe mode w/ LAN enabled.
2. Right click C drive
3. Select properties
4. Click on "update driver". It should find the driver and reinstall it.