W520 randomly freezes, now cannot be started and even reinstalled

I badly need your help!

I purchased my W520 (500 HDD, 8G, i7-2720) on 2011, and it has been working greatly. Since few month back, my W520 start to have a problem: it randomly freeze for no reason. The freezing can happen any time and even without use. The pointer/mouse, touchpad, keyboard and Ctrl+Alt+Del return no response at all. So everytime I have to use a hard restart. At beginning, I thought it is due to some viruses. However this still happens after I reinstall the system using recovery function. I did installed all updates after the installation. It is also unlikely related to overheating as it happens under no use and temps around 60 degrees.

Very recently the problem went worse and it was freezing very frequently. So yesterday I tried to reinstall the system again. However this time it freezes during the reinstallation process (twice). I have to use the hard restart again! After that I found the computer is totally dead. I can not start my computer or start the reinstallation process at all. It looks like the recovery disk has been damaged.

Now I have two primary questions:
1) What is the reason for the freezing? Could anybody give me your thoughts? is it likely a hardware problem or software problem?
2) Now I have to make the computer work first. Should I get a clean Win-7 or Win-8 system installed? or I should purchase a OEM CD for installation?

Thank you in advance for a feedback!

 

I had similar issues with the W520. My problem was screen corruption when moving the computer. I know you say that your problem occurs when the W520 is stationary. The issue for me was the memory door cover and static causing the trouble. There are threads at the Lenovo forum on my issue.

If you have warranty now is the time to make the call.

Brad