Need some more information, doctorjay.
When it boots up to 80%, can you get an Activesync partnership?
If you can, here's the A02 WM5 ROM for x50v:
Drivers and Downloads
Of course, the setup uses Dell's own installer for ROMs. It DOES NOT use the bootloader.
If you cannot, tell me and I'll extract that setup file into "the files you can put on your sd card"

A better word would the "Bootloader files".
One more thing, I don't know if you have any data on that Ax. If you do, we need to get it out before you do anything.