perley, if you use these methods, it will be clean:
1. How to wipe the OS from a BlackBerry device? - BlackBerryFAQ
2. How do I wipe the BlackBerry using Jl Cmder? - BlackBerryFAQ
Routinely, a TMo device such as your BB will not roam to Cingular due to their local roaming agreements. Ask locally of your carrier.
To install the third party applications without the error you are getting, install your handheld OS to the PC: Application Loader Error - BlackBerryFAQ