I can't imagine why you'd need to re-install the 7.5.3/7.5.5 OS you just put on your CF Card, unless you just dragged the folder from one partition to another. With only 8MB of built in RAM in your current config, as shown in your screen shot, you probably don't have Mode32 installed. Just install some higher capacity SIMMs and do your thing in the Memory Control Panel!

Actually, didn't you already have 32 bit addressing toggled ON in order to have activated Virtual Memory? :?:

Is your clean ROM SIMM already installed?