I had the same problem, and I found a way to fix it without flashing it.
1. turn on your phone (you should still be able to receive call and all)
2. call your self from a different phone.
3. Pick up!
4. Hit back button or home . The purpose is to get the curtain notification to work.
5. pull down the notification, I HOPE you have advance task killer install!
6. open advance killer, you will see a list of programs that are running.
7.wait for it~ T-mobile App pack or Market app, will run randomly sometime.
8. Once you see those on the list, long press, and hit Switch to!!!!
9. YES you are on the market! download launch pro or LG Home. (i did launch pro)
PROBLEM FIX.
*sidenote, you can long hold the search key, to do a good voice search. To launch browser and other programs, which will allow you to get the notification curtain .
Best of LUCK!