how much can i get for this?

i was wondering if you good people know how much i can get for my system spec's are below

compaq deskpro EN SFF C500
processor is upgraded to 900mhz
64mb ram i am also going to up the ram to atless 200mb
on-board video
new 40gig hdd
nic on-board
front and back audio ports
new modem
new laptop cd-rom
xp pro with SP1

and this is what it would come with

CanoScan FB620P Scanner with cd and its book
GEM 17inch monitor
HP 540Deskjet printer
new logitech optical mouse with everything that came with it even the box
compaq keyboard
all cables even a networking cable and spare power cables and this system has never been overclockedand i might up the video to 64mb befor i sell and please tell me if you think there is anyroom for inprovments