This was shown to me by PokerPot! Credit to Him!!
Here is a description of forced roaming:
If you're in a poor signal area, your phone will switch over to a different network to allow you to make the call. This is great, but the problem is that as soon as it senses even a faint Sprint signal, your phone will jump back on to the weaker spring signal resulting in more dropped calls and poor call quality.
What forced roaming allows you to do is to stay on the stronger signal network. Your phone will disregard trying to get back on the Sprint while you're on the call. Very useful. Unfortunately it only works on Sprint as far as I know!
Here is how you add it to Sprint:
HKEY_LOCAL_MACHINE\SOFTWARE\OEM\InitProv\PhoneSett ing
Change the ItemCount to 3
Add a String Value called "ItemName3" with the string being "Roaming Only"
Add a DWORD called "ItemValue3" with the DWORD Data being "5" (in Decimal)
Or just install the cab below and soft-reset!!