In case you didn't know you can install both Ubuntu and Windows 7 side by side so all you need to do is restart to boot one or the other :D Here is a guide Dual-Boot Windows 7 and Ubuntu in Perfect Harmony
Dirty Alpha 3.6:
This is a small update to add a boot animation ring tones and alarm sounds.
You should be able to get away with just wiping cache and flashing.
Good luck!
Team Hydro