iPhone rebooting itself?

[DiSFLyLaTiNa]

Its jailbroken 1st gen 2.2.1 I use Cydia. I don't understand why my phone keeps crashing! i'll be sending a text message and it'll restart. or i'll receive a text message and it'll restart. I open cydia and it restarts!

it's really frustrating and I already restored it and re jailbroke it. it hasn't made it any better. so i'm asking what is it that i can do??

 

[DiSFLyLaTiNa]

sometimes it goes to a red screen and sometimes it's on a white screen. other times it freezes with like weird colored lines going through diagonally across the screen.

it's just really weird and I don't know what it is or what I can do.

can someone please help me out?