You know a good clue to follow up on it where he states the landlord was tossing things in to a skip. For you non euro types, a skip is a frontend loader with a stinger on the back.
Ok so impact damages. Let's go down this highway for a minute. The impact may have cause mem card, cpu, graphics card, and other items that plug in to get jarred lose.
Pop the hood and take a look. You're not going to know otherwise. You need a #2 Phillips head screw driver.
Update: I Google the Dell beep codes. According to the codes, this board has some major issues. You have to scroll down the page a bit to get to the beep codes. There's the triple and 4 digit codes and the single digit codes are right under them.