GSM = Phone only. No data netowrk available.
gprs = Phone, carrier data network available, but not authenticated to RIM for BlackBerry services. (No BB email, web or PIN messaging.)
GPRS = Phone, Data, BlackBerry services are available
edge = same as gprs, but faster data.
EDGE = same as GPRS, but faster data.
Wipe your BlackBerry using Javaloader or JL_cmder How do I "wipe" my 8700 device using Jl Cmder? - BlackBerryFAQ
and then follow this link: How do I upgrade the OS on my BlackBerry? - BlackBerryFAQ