MBF (Major Boot Failure)

Hello, I'm new to this and have always tried to resolve my own problems but, that's probably why I writing this and not surfing/gaming right now.
Anyway, I got the great idea of loading my XP-PRO on to one of my many drives and dual booting it with win 7/64 Ultimate, which is the current real-estate holder. That way, I can reload all my GTA disc, install my IP cams and Hauppage USB TV-capture device and my daughter can install her Sims games and anything else she wants. But, rather than educating myself here first, I dove in and it was all "Assholes and Elbows" after that (*Guess which I am).
Every time I would try to install XP, it would respond with a BSOD just as it tried to enter Windows. I started the process of elimination and two days later, I got it to install after turning off all AHCI settings in BIOS and disconnecting the SATA Drives....I didn't say it was a pretty install, I did feel elated though, knowing I got the better of it!....Until I rebooted and connected the SATA drives and reset the AHCI references.
It really tried to enter Windows, until the BSOD kicked our Asses I guess your wondering how this is a MBF, as stated above? Well,....I don't reallty know. I went to try some more "Hell Mary's" this morning and it kept tell moot / and FixMBR) but, my little DOS buddy kept telling me that those were no longer valid commands or something along those lines.
Is this enoough 411 to allow some helpfull advise, minus the jabs and comments about my way of addressing and resolving PC issues? I'm not saying they aren't warranted, but I know you guys are to professional for that.....I'm not.
Thanks in advance for your help. I really dug a hole for myself this time, and other than reloading 7 again and losing my downloads and all the searching and installing I done over the last two weeks, I am out of ideas.....Please don't tell me I have to reload Win 7 again.

First check for all the Win XP drivers for your hardware.
If your Win XP CD, does not support your Sata Controller, you will need to load drivers to uses at F6.
Load Sata Controller drivers with a floppy disk is the best way.
SATA Drivers - Load in Windows XP Setup on Dual Boot
OR
SATA Drivers - Slipstream into Windows XP CD


Dual Boot Installation with Windows 7 and XP

Always install an OS with all others but the target HD unplugged.

You'll likely need the SATA drivers inserted per Theog's post above as XP is too old for modern hardware otherwise.

If you need to repair Win7, unplug all other HD's, confirm the 100mb Systm Reserved partition (if you have it) or C is marked Active, then run Startup Repair - Run up to 3 Separate Times until Win7 starts and its boot partition holds the System Active flags. Partition - Mark as Active (Method Two)