I am very upset really, after spending my money buying it and you still have to worry about another things. I wish I can just get on with my work you know...

It would sure be nice if it were that easy. The PC's greatest advantage is it's flexibility and user options. Unfortunately, that same flexibility means there is lots of room for errors and with so many players (hardware makers and software programs) all "supposedly" following the same set of "standards", each eager to place blame on the other guy, it makes it rough for the user that just wants to get on with their work. There are other alternatives - Macs come to mind where you have few options, but a good chance they all play together fine.

Is there any advice you can give me to protect my pc?

From what? Incompatible RAM? Hardware failure? Improper installation? We don't know what exactly the problem is to know how to protect from recurrence. If the RAM you bought is correct for your computer and was installed properly, and your power supply is big enough for the added demands of more RAM, it should work. But "should" and "real-world" don't always play well together. Did you ensure there was no static build-up in your body before touching the RAM or the ram slot? This is typically done by touching bare metal of the computer's interior, not always easy with a notebook. Memory modules are particularly sensitive to static discharges and can be destroyed without you even being aware this arc of electricity even occurred. Of course with notebooks, you are stuck with the power supply that comes with it.

If the problem started with the new RAM, send it back. To keep this from happening again, all you can do is do your homework and ask questions, buy from a reputable supplier, then keep your fingers crossed and hope it works.

Making sure the RAM you buy (or in this case, bought) is right for your computer minimizes chances of incompatibility, but does not eliminate it. RAM can be finicky and sticks that pass every test can still refuse to play with some motherboards, or even other sticks.

Can you please tell me how can I find out what type of ram my laptop need?

We are trying to help you here, AkasiE5`, but you have do your part to make that happen. Both Dan and I have said to check your notebook maker's website for compatible RAM. I also said,

If you need more help, we need more information, starting with the make and model of the notebook.

We also need to know the error given with the BSOD.

Dan also said you need to look in the BIOS. Did you? For some BIOS, it would make sense for the BIOS to pop up a warning when you add new RAM as it would cause a checksum error from it's last known configuration (that without the extra RAM). This would require you to enter the BIOS at boot (see your manual for how), then select "Save and Exit".

These popular RAM makers have auto-scanning and/or manual entry RAM wizards to help you determine compatible RAM. For manual entry, enter/select the PC or motherboard make and model number and the wizard will list compatible RAM.

Crucial - Memory Advisor
Corsair - Memory Configurator (manual data entry only)
GeIL - Memory Configurator (manual data entry only)
Kingston - Memory Search (manual data entry only)
Mushkin - Advisor
OCZ - Memory Configurator (manual data entry only)
Patriot - Memory Search (manual data entry only)
PNY - Memory Configurator (manual data entry only)
SuperTalent - Memory Finder (manual data entry only)

The following retailers have auto-scanners and manual wizards. They sell brand name and/or "house" brand (re-branded) RAM.

Newegg - Memory Configurator System Tool
MemoryStock - Upgrade Configurator
18004Memory - Configurator

I recommend if buying more than one stick, buy matched pairs, or even the new matched trips for new tri-channel motherboards. That's still no guarantee they will work with your motherboard, but (if we can trust the RAM makers, and I think we can) matched sets have been tested to ensure they play well together - a good thing.

Notebooks are notorious for heat related problems. Interior cleaning is not a user task so the best you can do is keep the exterior vents clear and use a Notebook Cooling Pad w/ext. power supply.

hey sorry I've forgetten my password and only just manage to come back on here.

Thank you for all your help, but I've went to PC world and get it fix and everything. It all working fine now, and I got 2.50 GB of ram too.

The problem behine all this was the ram I bought from Ebay, it's not the trype of ram that will work with my laptop.

Thanks for the followup.