Acer laptop with random freezes

Hello guys!


I'm new on the forum and I've got a small problem.



It's about my Acer laptop (model 5672) with Windows XP Pro SP3.

The problem with the laptop is that he randomly freezes. It can happened each two days or each 5 minutes. It doesn’t matter what program I’m using. When he freezes, I need to turn him off by pushing the onbutton.
When I want to reboot he refuses. He powers on, but when he should be showing the white Acerlogo screen (splash screen?), before the booting of Windows, nothing happens and the screen stays black.
The only thing I can do is power him off and start over again. But when I power him off, I noticed that at the end, the dvdwriter makes a lot of noise.
Only after a while or a lot of trying (on and off pushing on the button) he boots.
The not appearance of the white Acerlogo screen (splash?) at the beginning of the boot process tells me this isn’t a software problem.

I also have to mention that he went back to the factory 3 times in 3 weeks. The first time the hdd was changed, second time the RAM memory was faulty. The third time, they said they "tested complete system=>system OK No trouble found".
I don’t know what the source of the problem is, I hope you guys can help me.

Thanks

 

UPDATE:

I've tried to read some cd's and some of them can't be read. If I put the same cd in another computer, there is no problem.

Same with a dvd, the dvd writer won't read them, but when I put him in another computer the disc works.
Data dvd disc don't have any problem

Maybe my dvdwriter is broken?

Can it be that my computer freezes of reboots when there is something wrong with de dvdwriter?