I keep trying to install WinXP Desktop on ESX and XP boots, to install but say no hard drive can be found.

follow instructions from this site for using LSI Driver http://virtrix.blogspot.com/2007/09/vmware-installing-windows-xp-on-esx.html except the download link doesn't work so go here http://www.rtfm-ed.eu/downloads/lsilogic.zip.

Reference:
http://communities.vmware.com/thread/68043
http://www.rtfm-ed.co.uk/?page_id=174
http://virtrix.blogspot.com/2007/09/vmware-installing-windows-xp-on-esx.html