warhammer 40k and expansions

last week i got a couple of warhammer installers from a friend... he said that the other installers are expansion packs of the game...if i install all the expansion packs, can i still play the original campaign? or the campaign of each and every expansion pack?havent installed the game yet because im scared that i might do something dumb and stupid... :pthanks for the help... :)

Expansions normally just add content to the game that was originally there. it shouldn't effect the campaign, other than giving more stuff. :)