Your laptop can't recognize the RAM that is not relate with the BIOS, it is relate with RAM controller, even you upgrade it and it don't help.
Some info for the BIOS (Basic Input/Output System), the BIOS selects candidate boot devices using information collected by POST (Power-on self-test), when the computer boots then the POST tests, identifies, and initializes system devices such as the CPU, RAM, interrupt and DMA controllers and other parts of the other basic hardware. The BIOS then locates boot loader software held on a storage device (HDD) and loads and executes that software, giving it control of the PC.
What RAM do you have? Your laptop can support up to 2GB means 2 of 1GB DDR2 SDRAM 533.0 MHz (SO DIMM 200-pin).