Installing Windows XP on an Optiplex 790 MT

This YouTube video may help. Also this page at Superuser.

besides JO answer, re: The PC can’t boot anything through the CD drive for some reason.

my 790 did the same (I was trying to boot from Win 10 dvd in uefi boot mode) and eventually I found out my dvd drive was defective even though it is detected in bios.  if you have another internal or external usb dvd drive you can try it.  these sata or usb dvd are not expensive to replace.

also with these old model it is usually good idea to replace cmos battery w a new one when there is boot issue.

a few things to check:

is the internal sata dvd showing up in bios detected sata device?

if you press F12 after power on, does the dvd device show up?

Win XP would require you choose legacy boot option to boot from dvd.

Finally, are you using a genuine Win XP installation dvd disc?  If it is a burnt copy that might cause problem sometimes.  try use a different desktop to test whether the disc is bootable

@redxps630​ The DVD drive is recognized in BIOS and it does show up in the boot menu. Also, I can read and burn files to it just fine on the Windows 7 installation that I already have on the machine. It is a genuine XP disc, not burned. I also tried with a burned one, but no luck. I have verified that the installation CD’s work on another laptop.

when you choose dvd as boot device on F12, does your pc not show a message: press any key to boot from cd or dvd?

if your pc does not show this message and ignores the Win XP boot disc loaded in dvd, try clear cmos settings of 790 by motherboard jumper.  and do not forget to replace cmos battery w a new one

@JOcean​ Thank you for your response, but that doesn’t answer my question :(

I can install XP on a VM just fine, but I want to run it on the bare metal itself. The drivers for XP on the OT790 can also be found on Dell’s website, so I have no issue with them. My issue is with actually opening the installer for XP, I tried from CD and USB, but it doesn’t even launch.

@redxps630​ I have replaced the CMOS battery with a new one when I bought the PC a week ago. And the PC still completely ignores the CD/DVD even after selecting it from the boot menu.

another possibility that your genuine XP disc does launch is that it is not SP3 (service pack 3).  some earlier Win XP does not have the sata driver included and therefore pc cannot boot from it in a sata dvd.  please upload a pic of your genuine XP disc showing its face. 

my thinkpad T61 does not boot from XP SP1 disc.  I prepared a SP3 disc which boots successfully.

There are genuine XP SP3 disc.iso on the internet or you can buy one on eBay.

This is the genuine disc I have, it is SP3. The ISO i’ve downloaded to burn on another CD is from the Internet Archive. I have verified that it is also SP3. 

Funnily enough, I first tried to install XP using a flash drive with XP RTM or SP1 (can’t remember) and it would actually boot, but would throw a BSOD with something regarding SATA drivers, and a 07xB Stop or something like that. Now with SP3 it doesn’t boot at all.

do you have another desktop pc to test this genuine XP disc is indeed bootable.
also do you have a Win 7, Win 8 or Win 10 installation disc to test those are bootable from the 790 dvd?

my defective dvd drive in my 790 also shows up in bios and can read/write files in Windows, but does not boot from Win 10 disc.  after I replace it my 790 boots fine from Win 10 disc.

note these old half height odd are optical devices that do degenerate and are not 100% functional.   I suggest you try a different sata dvd or external USB dvd

I had sometimes encountered similar situation that the PC completely ignores boot disc in dvd on some old Dell.

@redxps630​ The DVD works completely fine on the Win7 installation on the 790, can read from it and can burn files to different CDs. 

if the dvd can boot from Win 7 installation disc but not the XPS SP3 disc, it is damning evidence the XP disc is the cause of issue.  you may need to find a different genuine XP disc to try.

https://archive.org/details/dell-windows-xp-professional-sp3-oem

https://archive.org/download/dell-windows-xp-professional-sp3-oem/Dell%20Windows%20XP%20Professional%20SP3%20OEM.iso

@redxps630​ i’ve been trying carious dell reinstallation iso’s these past few days. burned it on cd, didn’t work. used programs to put it on a bootable usb, no dice. it doesn’t boot to the XP installation at all… but it boots when installing any newer version of Windows. Dell’s website has XP drivers for my exact model, so it’s definitely supported. And yes, i tried slipstreaming them with NLite. 

Re: it doesn’t boot to the XP installation at all… but it boots when installing any newer version of Windows.

that is very strange.

time to try a different dvd drive

my experience with old dvd: it would recognize some genuine disc but would not open/read some burnt disc.  I had one working burnt XP disc in other dvd drives but this old Dell I was using would not boot from it.

I think you had spent already way too much time on this drive.  time to try a newer working dvd drive.  yes I know this drive works for you almost all the time.