There are different types of RAM (DDR, DDR2, RDRAM, etc) so as long as you buy the right type it will work, you don't need to buy RAM form Dell or HP just because you have a Dell or HP
with DDR pc 2100 to 3200 you need to watch for high density or low density, ebay sells high density ram and it's not compatiable with low density and alot of motherboards. It's cheaper. If it's labeled 128x4 it's high, if labeled 64x8 it's low. Low is supposed to be highly compatable with motherboards. This does not apply to DDR2 and DDR3.