I am using Leveller, a terrain modeling app, that can use the additional 1Gb in WinXP Home. However, in addition to the /3Gb switch in the boot.ini, it required some code to be changed in the executable file in order to work. I thought I could change it myself with a binary file editor such as VEDIT or UltraEdit, but that did not work and the developer changed it for me. PLEASE NOTE: The /3Gb switch does not work on all systems and may cause a crash on booting, requiring an alternate boot disk to edit the boot.ini and remove the /3Gb switch. Yes, I learned the hard way. ;) Chris