OK, here is where you stand:
You can go back to XP.
You will lose all installed programs. You will need to backup all existing data.
You will have to format. You will have to reinstall XP from scratch....
Harsh, I know, but that's the only option.
Now we can guide you through that though, so you won't feel too lonely
We've all been there at some point or the other
.
1) Grab
VistaBootPRO, and install it.
2) Go to the "Advanced Settings" tab in VistaBootPRO and select "Delete Vista Boot Loader." Press OK on all the prompts, and then restart,
with your XP CD in the CD-ROM Drive.
3) At the drive prompt, delete (not format, but delete) all partitions; then make a new partition there and set up XP on it.
4) That should do the trick