iPhone 4, 4.2.1 Jailbroken, cannot restore + No Signal Tried many things.

Hi,
Bit long winded.. :o
I'm sorry for posting what seems to be an easily solveable problem to some people, but i promise, i would not ask, only i have tried many, many things.

I have an iPhone 4 with Firmware 4.2.1
Baseband Version 03.10.01-ICE_2_8

Jailbroken with Cydia. It works with Vodafone SIM in it, but sometimes that signal drops to nothing, no other network provider works on it, there is no signal.
I have tried many, many of the suggestions to repair it, and always end up at "Best thing to do is restore it, and Jailbreak again.

What i have tried
So, i have tried to restore it, on XP and Windows 7. I have TinyUmbrella, the newest version of iTunes, and i have also got iREB-r5.

I have tried editing my hosts file, also using TSS server (in TU), and using shift and restore to restore it.
I have downloaded ipsw's from iClarified, Here, iphoneheat and none of them made any difference. I have changed USB ports and PC's, and i have backed up and deleted files from iPhone backup folder.

I have done all of the above in UDF mode and out of UDF mode, and used iREB-r5.

I have received different errors depending on what way i am trying to restore it, Error 3194, 1604 and 2005.

I am really stuck now. Would love it if someone could please help, thanks for Reading. :)