I recently put an extra 2GB of RAM in my WinXP SP2 box to bring it up to 4GB. I then added the /3GB switch (or /PAE switch as it's known) so apps would be able to use up to 3GB of the total 4GB available. RT doesn't seem to like this. At first, I thought it was because I made this change after RT was installed but I'm getting the same error even on fresh installs of RT. The error is: If you can't see that graphic, it says: MMIO protection system failed to allocate protected MMIO range. MMIO protection has been forcibly disabled. It is strongly not recommended to start any applications equipped with PunkBuster system while running in unprotected mode! I currently have a dual-boot set up in the boot.ini...one with the /3GB switch and one without. I thought I would bring this to your attention.