Well My first question is this: Are you on 2.1 or 2.2.1?
2nd question. Do you have a recovery that you can get into?
to do that have phone off and the press and hold power+send+menu until you see the LG screen. This will boot you into Recovery if you have one.
If you have recovery.... then wipe all user data, wipe only data, wipe only sd/ext, wipe only android secure, wipe only cache, and finally wipe only dalvik cache.
Now with My Nandroid already loaded in the proper place restore it.
http://androidforums.com/ally-all-t...nteer-who-wants-go-back-completely-stock.html
Thats going to be the easiest fix with the least amount of steps.
Also the Rooted Froyo Stock Rom was created using Tridents guide.