Cannot Edit\fill data in Windows 7

I've use disk Director with XP for a couple of years and frequently need to edit data at the Hex level.
On this new laptop with Windows 7 Pro it refused to let me fill any data. Unfortunately the error message, if that's what it is, flashes so quickly it can't be read.
Any idea how to work around this? I might try another hex editor to see if that works, but I also use DD to partition and modify disks, so I'd prefer to stick with this.