Word07 running too slow?

i have vista basic, 3 gbs of ram. when i'm trying to write something on word, almost always, the words i type come visible in a second delay. it is not always happening. i've made a trojan search with ad aware and i have an active virus protector. i have itunes, windows live mail, babylon and last.fm open with word, and occasionally an explorer. 3gb ram should be enough for all these, dont you think? and the computer is new, so all the other things are high too. what shoud i do?