Dell Inspiron Laptop Wireless Internet Locked Up

As fate would have it, the warranty expired on the 15th of July - The computer is a Dell Inspiron laptop - running windows XP. After being left online overnight in a hotel with wireless internet it locked up. Currently we get different results (but all results end in a lock up at the windows screen) - usually it comes up with a screen saying "we apologize for the inconvenience, but windows did not start successfully. A recent hardware or software change might have caused this" (no new hardware or software was installed prior to lockup) It gives you options to try to start - (I can't remember what all it said - but safe mode was a choice and going back to a prior time was a choice) Usually it is just locked up and you can't click on anything.

Once I did get it to go to safe mode and I tried to do a system restore - It did go through all the motions of doing a system restore - but when rebooted - the same "we apologize" error was there - WHen I can click on a starting option it goes to the windows screen - the blue line runs for a few seconds - then it just locks up. Dell wants a small fortune to help me over the phone. This is my son's college computer. I was thinking he probably picked up a virus when he was online in the hotel. Is that possible? It has let me get into set up by pressing F2 during boot - but I have no idea what to do there (if anything) F12 is another option it gives - but it wont do anything when I push that.