Vostro 1500 Freeze & Noise Problem

Okay, i have my Vostro 1500 from more than a year now (i got it in Christmas as a present from me to me) .
I use an external Cooling fan and care for my Notebook, try not to be to harsh on it. I use it for University Stuff and a few Gaming, used to play Casual World of Warcraft & HoMMV, and a casual DOTA War3 gaming, though i left recently WoW and DOTA War3 isnt casual anymore.

I went for a trip to mountains a few days (5) kept my pc safe, unplugged battery, etc etc, battery kept it inside the bag it came with (the one that protects from electricity or something like that) PC inside a Protecting Notebook Bag with Air-dunno-what just in case.

After i came back i opened PC, switched On and Started WoW. It froze and started making some awful noise, i freaked out and turned it off by pressing the On button like 20 seconds, gave it time to rest and calm down myself and then switched on again, this time it booted smoothly, nothing happened and like 2 hours later it froze again and started making that noise. Again switch off but this time when i switched on screen wouldnt work. It sounded as if it were booting, but nothing was shown on screen.

Removed battery and used only AC/DC and it worked, put battery again and froze again while booting, again freezed & noise(from now on F&N), switch off (from now on SOFF), switch on (from now on SON), nothing happens, gets to windows all ok, 30 mins then F&N again.

A few days living with the problem of the unplugging battery ASAP as it gave that error and then it really scared me. It Froze and made noise without battery.

That means its a problem my PC has and its not my Battery giving it to my Notebook.

Today, i have had like 15 crashes (F&N SOFF SON > random time later > F&N SOFF SON > booting > No Screen working > SOFF SON F&N > omfg i may have lost all data omfg omfg > Boots P E R F E C T L Y. Hours of working without a problem then BAM F&N.

I am really scared, as i made an effort to buy a powerful PC (Core 2 Duo 2,66Ghz , 2GB RAM cant remember if DDR1 2 or no DDR (i guess 1), 250Gb SATA, Nvidia 8600,...) due to needs from university (im studying Engineering Programmer in Spain so sorry for my Bad English) i needed a Notebook, and i bought one that was much stronger/powerful/however-you-say-it than my old Pentium 1,5Ghz Desktop PC.

Sometimes when i turn it on the Boot Loading bar just freezes (without Noise). Sometimes at start, sometimes at the end, sometimes when i alt tab it in windows --> BAM! F&N... sometimes i click Intro then BAM F&N. Sometimes i am not touching a thing because im writing on a paper and BAM!!! F&N!!!.

Im freaking out i really need to know if my Screen burned out, has a bad contact or is it badly ... hmm pasted... (however you say it), and if its the screen, why the ing Notebook makes that AWFUL CRYING-LIKE-NOISE ...

Sigh... ANY help plz? >_<