i have one compaq presario 4506 system in there only 32 mb ram and 3 gb hdd so i buy 20gb hdd and 64 mb 133mhz sd ram to upgrade it. when i remove the old one and connect the new it shows 16 mb ram which is in mb (on board) and 8.4gb hdd size so i go to bios setup and select user and set head cylenders and sectors and change the size to 18 something and install win98 but i am unable to use the ram it didnt show 64 mb i checked the ram in other system it is working. when i connect the old 32mb ram it show 32mb at compaq system. i go to compaq website and download the bios upgrade file and create floppy and install but it didnt detect the 20gb hdd (it still show 8.4gb if i select auto) and the new ram. how can i upgrade the memory. is there any junper settinge. on the motherboard. if i select the user option in bios for 19 or 20gb something the system didnt boot. after i change to 18gb something it is working . under head it shows max 16 head and 63 sector so i can max. the cylenders only MY HDD IS 20GB SAMSUNG. i am unable to get the correct head , sectors and cylender information for this hdd where can i get the correct information. in some other new system for 20gb it shows 255 sectors but i cant change it is max to 63 only.