This post is another effort to save people time and headache. Last night I decided to wipe Vista off my laptop and replace it with XP. I booted from my XP disk and chose to delete the partitioned space on my HDD to make a completely clean install. Vista was wiped off fine. Somewhere between that and a finished install of XP, something happened. I walked back to the living room to find my laptop stuck at the startup splash screen. I've got an Alienware laptop (piece of crap), so the big white letters of the ALIENWARE logo were stuck on my screen. Nothing would get it to move on.
I tried a series of things that DID NOT WORK:
1. Pressing DEL to get into the BIOS Post screen showed that it recognized several components, but when it got to the hard drive, it froze (the code 0078 appeared in the bottom corner of the screen).
2. I tried pressing F8 once I was in the BIOS Post screen to select my boot device, but nothing happened.
3. I tried booting from CD, and the drive would spin a little, but nothing happened.
So, here's what I did that eventaully worked. USE CAUTION when proceeding with these steps. It requires you to work with the internals of the computer WHILE IT IS POWERED ON! This is usually not advised, but I was desperate.
First, unplug your hard drive from the laptop. (Be sure you disconnect the right end of the cable. Don't disconnect the cable from the motherboard. It should have a sticker that says M/B). I recommend leaving the cover off for this entire process.
Next, power on your computer and press whatever key will allow you to select the boot device (mine was F8).
Insert the CD for installing XP (or, at this point, any operating system you wish).
Once the CD has booted, BEFORE IT SEARCHES FOR YOUR HARD DRIVE, flip the laptop over and plug the drive back in.
For me, these steps worked. I believe that when I initially tried to install XP, I somehow corrupted something on the HDD. When the computer defaulted to booting from the HDD, it simply froze. There was no way to get around it unless I removed the HDD all together. We are essentially tricking the computer to boot into CD, and then before the CD has to recognize the drive, add it back to the system.
If you are able to boot from CD with no problems with the Hard Drive removed, then these steps SHOULD work for you, assuming your HDD is not fried completely.
DISCLAIMER: Please be extremely careful when working on a computer while it is plugged into the AC outlet. I suggest working with one hand in your pocket if possible, and minimize what you have to do beforehand. Unscrew everything so all you have to do once the power is on is unplug it. If you feel like you aren't able to do this safely, don't do it. I take no responsibility if you get electrocuted or if you fry something else in the process. Take your laptop to a repair shop and see what they can do.