Man, I thought he was talking about a Malibal Nines or a Falcon DRX.
Meh.
- Look for a temp/fan monitoring suite (model/brand-specific if they exist). That, and a good cooling pad, is what I get for all my laptops right out of the box. No exceptions.
- Adjust power options. If it's a desktop replacement, you're likely not gonna want it to dim/sleep on you every 10 minutes.
- Remove bloatware. No need to go overboard, we aren't living in the era of 256mb ram Celerons anymore. Your machine can handle a few extra manufacturer's apps, especially if it's some sort of updater (do NOT delete updaters).
- It likely came with some kinda trial antivirus or whatever. Ditch it and get a free replacement, there are plenty of good recommendations on the board here.
- You mentioned "dorm", so I'm guessing "student". Grab a free office suite which you'll be needing for your assignments, term papers, and other stuff (like resumes, or prank April Fool posters). Openoffice works, or LibreOffice if you want to leave the OO ship like the devs did.
- OPTIONAL: buy a printer; bonus points for colour. Your entire dorm will love you. Trust me when I say there's nothing worse than finishing a paper only to be unable to print it and having to wait until the weekend is over for the student union / office supplies store to reopen. The ability to print your assignments at will is a
massive godsend.
- OPTIONAL: password-protect your machine and get one of those safety locks. Dorms usually mean "private property" = "dorm property".
That's about it, really. The rest of it is likely gonna end up being games, a bunch of p2p clients, a bunch of chat clients, and hopefully a good calendar/scheduling software so that you do not accidentally schedule a hot date at the same time you're supposed to stop by the student union for that part time gig.
Good luck.
Edit:
Dang, how could I have forgotten the good ol' media player standbys. Get VLC & Winamp, or whatever players of your choice are. Even if you don't watch movies yourself someone in your dorm likely does (and you can rent them the use of your machine,

).