stuck on white screen, jailbreaking iphone 4 ios 4.2.1 w/greenpoison

I need help, and i cant' seem to find a solution online anywhere. I have and iphone 4 running 4.2.1. windows xp, greenpoison rc5 b4. I have not restored my iphone. upon running greenpoison i go through the steps in order to put my phone into DFU mode. then itunes pops up on my comp. and add new hardware wizard. Greenpoison then goes to jailbreak, when i push jailbreak greenpoison runs alittle and then my phone goes to a white screen. the problem now occurs. The white screen does not go away, watching videos on youtube i should see code on my iphone screen but i see nothing but a white screen. what should I do? anyone else have this problem and got there phone jailbroken? i've tried numerous times. Add new hardware does not show up anymore, itunes still does, and the white screen on my iphone always sticks, then i have to hard reboot to get phone to come back on. pleaes help if anyone can

 

after a bunch of messing around I figured this out sorry for any inconvenience on anyone. The problem was when I entered the phone into DFU mode my comp goes to add new hardware and when clicking continue the hardware was not installed properly it said. This was due to bad drivers, non updated, who know. what worked was uninstalling itunes, and all apple related programs (apple mobile device, apple update, itunes, etc) and reinstalling then upon jailbreaking again and entering DFU mode, add new hardware showed up but this time i got the message hardware installed successfully.

 

boss,, just restart pc...and use itunes 10.1...
and repeat procedure...dont worry your iphone is in dfu mode already...
after you open gp wait until says release the power botton before you insert usb in your iphone....