a message keeps coming up telling me my windows 7 is not genuine. i bought the computer from dell and it was already installed on it - are microsoft right to tell me it's not genuine? what can i do about this? (i did validate my office word though, and that went fine). if i don't do anything, will something bad happen (apart from these messages coming up)? is there a way to stop the messages?

CALL Dell if you just bought computer and haven't done any thing to it.that computer should have been ready to go the instant you turned it on. Later---

Call Microsoft, if you don't do anything it will lock you out after hmm 30 days? or was it 60.

Yeah but the point is it will lock you out

If I'm not connected to the internet, how I will get rid of this message and its black screen???

i believe you can get an additional 30 days of trial use to optimize os usage.
just go to "command prompt" key in slmgr.vbs /rearm -> and then execute.

and if your windows is genuine ,the not genuine is usually the results of a virus or trojan

Contact Dell for a replacement, and insist that they also send you an installation disc so you can reinstall the OS if this happens again.

You should call DELL customer care and discuss the issue. Do not call Microsoft for it.