Computer freezing when files are coping

I have some hardware problem which I cannot understand where the problem is. My laptop is freezing when I trying to copy some files form USB, External HDD, DVD ROM, through network, even to different folder in the same partition. My first guess was HDD but I tried with new one but I still have problem. I tried with new memory module but nothing. It is worth to mention that problem come up only after 15-20 minutes after laptop is turned on (in first 15 minutes there is not freezing), I cleaned processor and temperature of processor is not the problem (but definitely there is something with temperature because in first 15 min he is working fine). I tried Linux, Windows but the problem is the same. After my laptop is freezed only Power button works to turn it off. Computer freezes not only when coping files but such situation is much rare in compare when coping files.
I have laptop Fujitsu Siemens Amilo Pro v2055 (4 years old) and I want to hear some other opinion before I take it to some computer service.

 

Does it freeze up when NOT coping files ? How does it run normally ?When was your last Virus scan ?

 

When I NOT coping files it freeze, but occasionally, maybe in every 2-3 hours once. When I start coping files he freeze immediately in first 10 seconds of coping. But when computer is cold (when it is just started) he will not freeze in first 15 minutes while files files are coping.
He don't have viruses, I try it on Linux but it freeze there in the same way.

 

Hi,

Maybe the Hard drive is getting too hot during the copy process. Also, you may want to try running Memtest86 to rule out the possiblity of bad RAM as well.

 

I tried with Hard Drive form another laptop and with another RAM, also I run Memtest87. Maybe it is problem in CPU or some chip in MotherBoard, my guess.

 

Maybe you could try running Prime95 to stress the processor and see if it comes back with errors to see if it is the problem?

 

I just tried Prime95 and everything runs normally in first 45minutes, then I inserted USB Flash and laptop freezed immediately. It seems like when there is some communication between USB(or DVD Rom, or Ethernet) and Memory I guess, then laptop will freeze (but not when it is cold - in first 15min)

 

Just for record, I find where is the problem. The problem is overheating of South Bridge which happens to have all notebooks from this series (Fujitsu Siemens Amilo Pro v2055).