Connect to iTunes and look to see if you can access music apps etc. If it is in dfu mode you should see any of that. If you do see that, then sounds to me like a bad LCD. Which is a cheap fix with plenty of tutorials to guide you through the replacement.
When connected to Itunes the RECOVERY windows pops up everytime without fail. So i do not think it is a faulty LCD. I might be wrong... and suggestions?
When I try CUSTOM 4.2.1 i keep getting Error 28. Any help?
When in DFU, hold down the home button and the power button for about 10 seconds. If your phone is connected to your computer you'll hear a beep as when a USB device is disconnected.
Next just press the power button and your phone will startup at usual.