Laptop freezes randomly: tried all I can think of

[veling]

Laptop is HP 625 model.

It freezes randomly so I re-installed win7 as it worked fine for few years now.
It was useless, freezing again.

I read forums and see it could be rootkit virus, so I downloaded TDSSkiller (it already has avast on it, which I installed immediately after fresh win7 install), malwarebyte antirootkit and ran them in windows, no sign of virus in reports.

Temperatures are all good in this laptop, recently changed thermal paste, cleaned the fan and its keeping it cool without any problems.

Then I figured, its either memory or HDD.

Here it gets tricky, I downloaded various HDD and memory tests and burned them on CDs in bootable form, but each and every one of them hangs randomly. Cannot finish a single memory test. It hangs on start or 5 minutes after start...
Same thing with HDD tests except with win7 recovery console tool that tests memory. Memory test in recovery console proceeds until the end and reports no errors but it hangs again.

tried some bootable rootkit removers they also hang after starting.

Main problem for me here is that even though I ran these tools in DOS environment it still freezes....

I am truly without an idea here, hopefully you have some suggestions for me to try...

Thanks

 

[veling]

Update:

I removed the HDD and installed a different memory bar. After doing so, I tried to run memtest86, 86+ and memscope... Again, laptop freezes...

Now I dont know what to think....

 

[the_french]

Hi, I have also a HP 625 laptop that I have now for 4 years.

I encoutered the same problem of freezes. I think it is not a problem of software neither a problem of rootkit.
The thing is I have Windows and Linux (xubuntu) and both of them freeze.
I have just a nice little blue screen with vertical strips more...

It may be the radiator which could be blocked by some dirt and would provoke an anormal heating of the system but I'm not sure...