Hello...
I'm really new to the nextel 7100i BlackBerry, I have nextel already as a service but I was using a i730... I put my sims card into the Blackberry and I turned it on, it acts like if its loading and then goes to a white page with a circle with like a little tape with a circle, square, and a triangle on it, also has a line going through the whole big circle like if u seen a do not smoke sign with the line going through it and then under the circle it says 507... could anybody possibly try and help me out with this situtation... it would be greatly appreciated, thanks!

Sweet--welcome to the Forums!

Error 507 means no operating system on the BlackBerry. Is it new or used?

Here is what you need to do... read through this link, and you can start at Instruction #2, under "Wipe the Device" where it speaks of the 507 error.
How do I wipe the BlackBerry using Jl Cmder? - BlackBerryFAQ

If that does not work, you might want to walk through that FAQ link from beginning to end to make it work.

The 507 error is not a big deal, and IF you follow the instructions eactly as posted, you will be fine, i believe.

Good luck.

also you may want to add the data plan so you arent suprised by a nice huge bill. They are notorious for adding a data plan and you get a huge bill you are not expecting. I had that exact thing happen to me, I came over from an i730 as well. Didnt realize what a BB was. I though wow cool phone didnt realize it was an expensive phone.