dude who told you that you cant change ram??
Dell said the Optiplex GX150 can only take 512mb total.
Dell said:You can increase system memory up to 512 MB by using synchronous dynamic random-access memory (SDRAM) dual in-line memory modules (DIMMs). The system board illustration shows the location of the DIMM sockets on the system board (DIMMs must be non-error checking and correction [non-ECC]).
Is there any other way?