Reset & Re-Install Samsung Galaxy S i9000

Hi all,
I have a Samsung Galaxy S i9000. Its an Australian phone with an Australian provider modified OS. When I upgraded to Froyo it was slow as all hell. I had to use the oneclickfix to fix the lagging. Its definitely better, but I have seen other phones that didn’t even need this fix after froyo was installed. In order to fix the lag I needed to root the phone.
Anyway to cut a long story short, is there a way I can completely format everything on the phone. I mean back to have nothing on there and then install an unaltered version of Froyo. I don’t want Gingerbread at the moment. If someone could assist me with some links and work instructions it would be much appreciated.
P.S – I know I need to backup my things and I know how to do that.
Thanking you
Answer #1
I think this could help :
http://www.addictivetips.com/mobile/how-to-root-and-unroot-samsung-galaxy-s-i9000-with-a-single-click/
Answer #2
Make a jig
(Basically a micro usb input with a 301k resistor and a bent over piece of wire).
Answer #3
http://forum.xda-developers.com/filter.php?cat=Samsung-Android
all your answers found here, patience and read thoroughly
Answer #4
I have the same device which is from a Australian Telco, basically I had a bunch of applications from the Telco that I never used and I wanted to unlock my phone. Easiest way is to root your SGS then use Titanium backup to manually remove each telco app installed and the previous link is a good community to find out ways to root your device, also try using Youtube.com to find some tutorials if you are unsure.
Answer #5
Answer #6
Guyz, thank you all so much for your help. Apologies for the late response. Your feedback has been very helpful to me.. MUch appreciated and thank you again.