It depends on what type of RAM you are using. I'm assuming PC100 or PC 133 SDRAM. Are they Single or double sided. The double sided or highest RAM is put in slot 1 (nearest to the CPU Processor) Check your Motherboard specs if you can for the configurations. If you have two sticks of 128mb = 256mb Windows will use some of that Memory for Graphics, so you will never see the full 256mb RAM in a System view.....192mb RAM sounds about right. You can always change how much Windows uses for Graphics in the BIOS, but I wouldn't set it below 32mb.
Hope this answers your question