HT1338 Can I use windows xp on OS x mountain Lion?

Question

Can I install Windows XP on OS X Mountain Lion?

Answer 1

Installing WinXP on Lion or above without BootCamp
It is possible to install WinXP onto Lion or Mountain Lion.  Bootcamp does not work thanks to Apple removing support, but the important drivers you need can be found on the net (details below – but the drivers you need will depend on your hardware). WinXP when installed will display at a low resolution on your screen but with the drivers you can fix that and get Wifi connectivity. 
When I did it, by far the most time consuming part was to get my XP upgraded to SP3.  The solution to one nasty problem with SP3 upgrade is given below.
PREPARATION
Obtain the following files using your browser in OSX before attempting WinXP install.
1.  Service Pack 3 file (if your WinXP is Service Pack 2).  Obtain from http://www.microsoft.com/en-us/download/details.aspx?id=24
If the file has moved to a different page search on Microsoft's site for it.
(Note: I downloaded the SP3 driver written as a CD disk ISO image and used the FreeISOBurner software to make a CD from which I could make the install.)
2.  Search and find drivers for the Intel graphics of your Macbook Pro
(search for  'Intel® HD Graphics Driver for Windows XP')
3.  Find drivers for WIFI.  Mid 2011 MBP uses Broadcom. BCM43xx
Wiki drivers site has them.
4.  Make sure you have Win XP installation CD and the 25 character licence key.
Give yourself some time without too many urgent deadlines etc. 
PART A
Partition your hard disk in OSX using Disk Utility.  One should be FAT32 format and set to your size needs for Windows XP.
Restart computer and hold down C key to boot from Windows XP installation CD
Install WinXP following instructions.  At least one restart required.  Hold down option key when power is down to select the windows drive for booting
Once finished WinXP set up, restart and boot into OSX pressing and holding the option key when power is down.
PART B
From OSX, open a finder window and locate the Windows drive
Open the folder 'Windows Drive'\Documents and Settings\'Your windows account name'\Desktop
Transfer the files you will need from your OSX into the Windows desktop
Service pack 3
Intel Graphics Drivers
Wifi Drivers
(Note.  This is where it helps to use FAT32 format for Windows.  If you choose to format using NTFS when installing Windows then OSX can read but not write to that drive.  If you use NTFS you will need to transer the files to FAT32 formatted memory stick or CD)
PART C
Reboot the computer into Win XP by holding down option key when restarting
Install the Intel graphics drivers.  Reboot to XP
Install the Wifi drivers.  Reboot to XP
Have a go at bringing your XP up to date.  This can be a long task depending on which version of installation disk you own: XP, XP with SP1, XP with SP2 or XP with SP3.  In my case I started from XP SP2.  Unfortunately the Windows Update mechanism in the XP SP2 system is now blocked by Microsoft so you can't update using the web.  This is where you need the SP3 installation.
There are many possible headaches:
One error message is 'Setup requires a minimum of 4 additional megabytes of free space' when running the SP3 installation.  If this is the case then go to this page:
http://answers.microsoft.com/en-us/windows/forum/windows_other-windows_update/er ror-there-is-not-enough-disk-space-on/3109444d-2249-4e66-973c-bd662635dc77
It appears that the BootDir register is not set during some installations (mine included).  Follow the clear instructions from David Mitchell to fix the registers (Thanks David!)
PART D
Once you have Win XP SP3 going then you're Wifi should work and you should be able to complete the update process using the Windows update mechanism.  You can then find other drivers you may need such as LAN drivers etc.