holy cow, thats a lota crap running. on my bro's laptop running XP pro, i got it down to just 13 runing process's without programs running, and only 1 or 2 startup progs.
the registry setting wasnt hidden at all. i found it at /HKey_current_user/softwere/adobe/photoshop/7.0... 'memory usage'
im also running 512ram right now, the value is set to '32' witch makes it show up as 50% of ram usage... wel u can at least check the setting know acording to my value's.