Download HDDUnlock
here. Unzip it, and put the files on a floppy dos boot disk.
Connect the drive to the PC, and boot into DOS using the disk. Run hdunlock.exe choose your drive, then enter the master password TEAMASSEMBLY. Then run hddisabl.exe and again choose the drive and enter the password. It should say done, and the drive is now unlocked.
Once you have got the eeprom.bin off the drive (in another xbox), and assuming your xbox is flashing red only (not red/green)...
Download XBTool
here. Open up a X2 bios, embed your eeprom into the bios, and save it. Flash the new bios onto the modchip, then put it into your xbox. Hopefully it will bootup, and you can use configmagic to fix the actual eeprom on the motherboard.
Some people have said that the embedded eeprom still wont boot, so you can also try:
http://arisme.free.fr/Xbox/Reflash/or
http://rex.xbox-scene.com/I2C/i2c-prog.html -EEPROM stuff at the bottom of the page. I have used this one and it works great, but most people find the other methods easier.
Goodluck