Unable to install Windows XP on my MiniPC without erasing all partitions

Hi folks,

I recently encountered a security problem on my miniPC and had to re-install Windows XP. To do that I followed the instructions as on http://www.liliputing.com/2008/04/install-windows-xp-on-mini-note-usb.html. However, the author of this note says in #5 of the "Installing XP on the Mini-Note"-section that you should delete all of the partitions on the hard drive. This is something I cannot do since there is essential data on the D-drive ! So I didn't erase the D-partition and, like the author foresaw, the PC returned a "Hal.dll missing" error. I understand this is because I didn't erase all partitions on my hard disk. My question is therefore: is there a way to install XP WITHOUT erasing the D-drive ? If not, how can I salvage the data from the D-drive prior to rebooting it ?
As always, I appreciate any help !

Erwin
Belgium