Help Need urgent help on unrooting.

[IndyJones1023]

I rooted my Sprint Samsung Galaxy S II Epic 4G Touch with the Zedomax kernel but started experiencing severe loss of signal issues. I jumped to the Odexed-Rooted-Busybox-EG30 kernel and still had issues. So I followed the stock recovery video seen here and it doesn't work. I've repeated the steps 3 times now to no avail. I still get the yellow triangle on boot up and Superuser is still in my applications folder.

Any help, please?