I am writing to ask about a problem with my computer. First, I would to apologize as English is not my main language and thus, I am not familiarized with most of the terms.
Since two months ago my computer simply freezes when I leave it for a short moment. The way it freezes is that there is no way that I can use the OS again, I can do any operation once but afterwards it stays "thinking". For example, let's say that I go to the bath and I leave firefox opened, when I come back I can minimize it but afterwards I cannot do anything else. If I don't have any program opened (let's say from a new reboot) and I leave it, then I can open "MYPC" or whatever but I can see the mouse icon in the "thinking" status (forever). It does accept any input from the keyboard (although pressing caps lock, num lock, ... lights the leds in the keyboard). It does not matter whether I press ALT+TAB, CTRL+ALT+SUPR, ... I do not have any other choice but to manually restart it.
I have been testing the memory both, with different softwares and manually (by removing them one by one (I have a total of 4*4GB), switching them, working only with one memory, two or three memories (trying all the combinations)... The problem still remains so I assume that is not a memory problem. Additionally hard drive tests turn out to be positive (I mean that everything seems to be working perfectly).
I have also tried to unplug/plug all the connections in the CPU but nothing happens.
On the other hand, it seems that sometimes (when I am lucky so it can also be a coincide), after shaking my CPU it seems that the problem disappears and I can work for one of two days (but I have been lucky only three times in the last two months).
I have the feeling that the problem has been becoming worse and now my computer freezes whenever I leave it (before it was like 70% of the times, now it is Always) for a short moment (lets say for 5 minutes approx.). On the other hand, the interesting thing is that I can work with it perfectly without any problems for hours. It happens only when I leave it idle. Of course, I have tried to disable all those features that turns the hdd into sleeping move, screen savers, and so on (everything in the power settings)... all the features have been disabled... I should also mention that, as my computer is fine while I am working with it, I have tried to make some programs that runs it indefinitely. For example, I made a loop that solves a tedious equation and once solved it redoes it (in a loop). I have also created a script that copies a large file and deletes it, copies it and deletes it.... and I have also made a script that every minute opens Microsoft Paint software with a picture and then close it again, and so on.... My idea was to keep it busy when I leave.... in any case, I was no lucky

Finally, I have also tried reinstalling Windows 7 (so that I can access my old files from the windows.old folder) and I have also installed Linux Mint in another partition. It happens the same so I assume it is not a operating system problem....
My guess is that there is a component in the CPU that, whenever it slows down or whatever causes the problem.
Is there any solution for this? my computer is new (only one year and a half) and is under warranty but the problem is that I will leave USA in two months and I am not going to send it to repair as they already estimated almost a month for the repairing.... I would prefer to work as it is and once I leave send to repair (the computer is from the office, not mine). There is an electrician engineer which I could ask for help in case someone knows what could be causing this problem. Additionally, if someone knows how to "force" the computer to simulate any human task I would really appreciate it. That way even if I cannot fix it now, an alternative to prevent whatever is crashing it to happen (every time I leave it idle) that would be nice.
Does someone know what could be the main causes? does someone know how could I trick "windows" to emulate working operations?
Regarding to my computer it is a dell, Windows 7 (64-bit), 16GB memory, 1TB hard drive, Intel® Core i7-2600 CPU @ 3.40GHz
Thank you very much for all your help.
Best Regards