I just tried to install Windows XP on my old Windows 7 laptop so I could dual-boot. For some reason the installer DVD crashed while preparing to setup (so setup hadn't even started) but now the system won't boot into Win 7 either and I'm stuck being unable to run either.

I have several machines with dual boot (even triple boot) and never got any problems. Your problems is because you tried to install an older system over a newer system, and Windows doesn't support that.
What you need to do:
1. Try using your Windows 7 DVD to repair Windows 7 boot and installation (it probably became corrupted by your atempt to install Windows XP). You will not, however. be able to install Windows XP.
2. Format the HD (I use two HDs for this, never a single one), and start installing Windows XP.
3. After Windows XP is installed and running, install Windows 7 IN ANOTHER PARTITION. Windows 7 recognizes automatically that there is another system, and will create a boot option that will let you choose which one to use when starting up.
This is not stupid. Actually, it's much better than Mac way, which will force you to keep ALT key pressed each time you want another system.

BTW - by mounting your HD in another system, you will probably get access to it, and recover all your files. You should do this before anything else, of course.

I am not sure Win XP can be installed after Win 7. It crashed maybe because you did not supply the needed SATA drivers during boot of the setup.
You may use the XP mode inside Win7 if you need this for older programs.
Now you can just try to make a repair installation when booting the Win7 DVD (or trying to reach the W7 boot menu when starting from HD fro repair/return to previous state)

No I didn't, I did it the same way I have always tried to set up dualboot which is to run the install DVD from the bios boot from DVD loader and ask it to create a partition and DB setup - it's just the installer failed twice.

Anyway seems like a glitch Win 7 is booting now but I still can't run the setup DVD

Doesn't work for drivers though

That's a possibility but if so how do I do that? I don't have a separate set of drivers.

Durin boot of WinXP setup it asks you to press a function key to load additional drivers. Download Windows XP chipset/HD interface drivers from the notebooks manufacturer homepage and place them unpacked on a disk before installing XP.

Some laptop chipsets dont have drivers for XP. XP is over 10 years old and you should check the makers website to see if they support it. If not, you could be in for a rough ride.

And still one of the richest companies in the world...

Good luck with it, man.

I'm pretty sure, that's not the problem. The bootloader that's created automatically by Windows Setup when, during the installation from the Windows DVD, it verifies there's other systems already installed, only works for the same or newer systems. EG:
1. You have Windows XP, and want to install another XP. Setup creates a bootloader automatically.
2. You have Windows XP, another Windows XP, and want to install a Windows 7. Setup creates TWO boot loaders. In the first, you have an option of Windows 7, and another that says Older Windows Systems.
If you choose the second option, then you have another option that asks you which of the older Windows systems you want..
3. You have Windows 7, and want to install Windows XP in another partition. I'm not sure, because I never tried this, bit I suspect it DOESN'T WORK.
Last edited by fmr on Wed Jul 04, 2012 7:43 am; edited 1 time in total

DELETED - duplicated post

???

most likely the win7 laptop has the bios set to raid or AHCI mode (required)
XP will NOT install on this period
and as mentioned doubtful the laptop has drivers for XP but most dirvers (intel chipset, video, nic can be had from the manufacturers website) things like webcam will not have drivers most likely

why in the world would you want XP anyway

What thing didn't you understand?