I did this the other day, you don't need to flash.
take out your battery,
turn it on by holding Power+Home+VolDown, you'll see it doing a factory reset.
It will boot up exactly ONE time. To a blank desktop with a notification bar and no menus.
If you reboot, all you will get to is the android logo, thats it looping forever.
Send yourself a text message from another phone with
http://www.gmail.com as the content.
In the meantime, download any home launcher apk file and email it to yourself.
When you get the text, tap the link. Now you have a web browser.
get into gmail and download the apk file. When done, install it.
After you have at least 1 home launcher installed, it will reboot fine.
You can now re-install any apps you want.
I would recommend you don't have any incoming calls while you do this, it makes it so you can't access the notification bar when the text comes in.
Don't forget to enable usb debugging afterwards

.
Also it will still be rooted when u boot back up.
-K