I can't find any info about wether it's compatable or not with the sempron,, I'll check for the next 10 mins or so but you might have to wait for a reply from somone who knows a bit more about Cpus than I do.
keep in mind that your processor is 333mhz bus speed while your memory is 400, the processor will cap the memory (you'd want to get pc2700 or a 400FSB processor to really , cheaper way would be the 2700