My HP Pavilion dv6000 just shuts down instead of...

I bought a new HP laptop (pavilion dv6815nr) about 3 months ago and just recently, for no apparent reason, the pile of junk(which I treasured at first) just shuts off on occassion. Why this happens, I do not know and when I try to turn it back on, I either hear 2 beeps or 1 beep and it just shuts itself off, only resarting after multiple attempts or if I just leave it alone for a few minutes and then try. At first I thought it was dust blocking up the fans so I cleaned the vents with a can of compressed air, the results: no change at all. Then I said maybe its a POST error and I tried to reseat the memory modules but again my efforts were to no avail as the madness continued. The only thing I could think about next was that the battery overheated but it never got too hot while I was using the laptop, just warm-ish. Maybe the mother board just got fried but that can't be possible unless I bought a defectile pile of junk. Wait-yes I did probably buy a defective pile of junk as I never had any problems with my DELL computers or laptops.
Whether I was surfing the internet or playing a game, or just typing it just shut off....not even a warning except for the supposed POST error.I've never even dropped the laptop to tell you how confused I am. I have tried almost everything BIOS update, Nvidia driver updates, cans of compressed air, reseating memory modules but the blasted piece of junk (as I will refer to all HP products except their printers from now on) just hates the likes of me. Please if any of you techs have any help/suggestions for me I will greatly appreciate it.

Additional details:

BIOS: Phoenix BIOS
Windows Vista SP1
3 Gigs of RAM
AMD Turion 64x2 processor (2.00 Ghz)

Oh, and used system recovery to reinstall to factory TWICE trying to fix the problem and knowing my luck----you guessed it--- it didn't work. I also noticed that when I run performance demanding software this happens faster and when I close it until it hibernates and open it again, it shuts off. I don't want to do anything to void the warranty in case I have to send it in (although HP customer care is total **** and plus I live in the Caribbean and bought the laptop in the U.S.). Again anyone with any ideas your help is welcome.

1. I am facing a similar problem, i bought Hp Pavilion dv6330ea second hand from a guy lives in my city.... he made me fool (now i must say) as when he showed me to use it before buying , the laptop didnt contain heavy things.. like games, installers etc (in which high processing is required), i also didnt check it thoroughly (my mistake) but after two days of purachasing it, i installed so many softwares of my use on it and started burning dvds that was the 1st time is started facing the problem of shutting off the laptop. It happens like this:
   
   Laptop get turned off (like someone has pull off its switch) automatically. and the system happens to be overheated may be this is one of the reaso. But the problem is that in the most chilled environment (in chilled room having Air Conditioner) the same problem occurs. I feel that it happens when processor has to do loads of work, like i put usb and started accessing it at the same time i start opening so many webpages and burning dvds. But sometimes it also happens that when room temperature is 30 C and i am not using processer heavily it get turned off automatically .. may b coz of overheating ..but literally i am not exactly getting what is happening wid this pc ... literally this pc makes me embarrass at my office and social gatherings. I cant play games, i cant use it like it has to be used wid so many things downloading, listening songs movies heavily surfing etc but i cant i feel shy getting this wid me to my frnds .. coz i bought it after paying a huge amount of money and after a heavy market research about laptops. But the guy made me literally fool. I hope he wont be better off wid that money he got from me against this laptop, But i also suggest u to plz plz never buy used laptop.. they usually hav drawbacks!!!! ...
   
   I ask u ppl to give me suggestions and help me out so that i wud face my family and frnds wid this laptop. Keenly interested in ur responses!!! .. u can mail me at maazspecial@hotmail.com
   
   Laptop:
   
   HP Pavilion dv6330ea
   120 gm hddk
   1 gb ram
   P/N: GH878EA#ABU
2. it will be better if you ask your vendor for repair as it is in warranty period