Blue screen crashes usually involve a device driver incompatibility, usually related to your graphics card.

Instead of starting Firefox normally, hold down the Shift key to get the Safe Mode/Reset dialog, and Start in Safe Mode. Then switch your hardware acceleration setting here:

"3-bar" menu button (or Tools menu) > Options > Advanced

On the "General" mini-tab, uncheck the box for "Use hardware acceleration when available"

Safe Mode automatically disables hardware acceleration, but this change should go into effect when you exit Firefox and start up again normally.

Any improvement?

Sir, please. I've read through the forum about this issue. Yes i already disabled that hardware acceleration. It's not it. It's not a bluescreen. It's a full system crash. It won't even let mouse move.

I open firefox and whenever i type anything in the ominibox the full crash happens.

I was reading the forum and some step by step to fix this, it said to go and type "about:config". I'm just using this as example, then, when i press enter it crashed. Also if i click an old saved bookmark

Okay, BSOD = Blue Screen Of Death, so that's why I responded that way.

It's hard to recommend experiments when the results are so severe, so I'll wait to see what other responses you get.

Yes, sry but i didn't find any specific topic, that's why i posted it here. Btw i'm using Windows 7...