Using manufacturer approved RAM?

[Warpspasm]

My son got a Compaq PC for Christmas and it has a paltry 256mb of RAM. The thing is almost unusable. It takes DDR400, but do I have to use the one approved by the manufacturer, or will any DDR400 work?

Thanks

 

[Rugger]

It should take any DDR400 RAM. Do you have specifics on the system so we can verify the right RAM? Mobo and RAM info would be good.