Hello guys, I have started this thread elsewhere but since I am convinced it's a hardware thing, I will post it here now. Here is mid-2010 MBP (13 inch, 2,4 Core Duo 2 Intel), SSD 500 GB + 8GB RAM battery is about 5 years old Two weeks ago updated from Snow Leopard to El Capitan (+ insalled new Samsung SSD +8GB RAM + took out and cleaned the FAN). Problems: First days El Capitan was running really smooth (even after I installed some third-party applications). Boot-up super fast. Now, at times MBP stalls....even letters that I type can sometimes appear with a bit of delay,browsing of the web problematic, when moving across the Dock, the icons do not transition well - almost like a replay of a slow movie, plenty of spinning wheels when loading an application (including a simple application such as in-built Dictionary); on boot-up...now takes much longer, sometimes I get even blank white rectangle instead of seeing the "progess bar". Overall the system becomes unresponsive, extremely slow, becomes very difficult to use. My diagnostics: kernel_task. It can sometimes run up to 600% of CPU, sometimes 300%..fluctuates...as many as 110 threads open; uses most memory of all apps. When kernel_task is highly active, computer stalls (see activity monitor screenshot). I've noticed that this issue is most likely connected with OVERHEATING (only in the upper left-hand corner of the computer..ie. above motherboard). Placing fingers on the aluminium above the keys (ESC, F1, F2, F3) as well as left of keys TaB, CAPS Lock it feels really hot (almost a burning sensation).The same is true on the back of this area. If I turn off the computer or open the window and let it cool down, kernel_task problem disappears and system works fine for a while. FAN: I hardly hear any fan activity during this time (though the fan works generally...sometimes it is audible for a very brief period of time). Temperature(see screenshots): no big change in Battery point 1, Battery Point 2, Battery TS MAX, Left Palm Rest, samsung SSD. big changes (after cooldown vs. high numbers during normal use): CPU Diode (49°C - 75 °C); CPU Proximity (45°C -68°C); Northbridge Chip (50°C -73°C); Northbridge Point (41°C -57°C). Tests done: fresh clean install of El Capitan. Reset SMC several times; ran in safemode (couldn't perform Hardware Diagnostic Test yet). Disconnected usb-plugged in devices. All no effect.. The only issue that helps is to cool down the system by shutting it down and waiting (or opening window and letting cold air in). BATTERY(see screenshot): - whether AC is on or off, overheating is an issue. But I have another problem: "SERVICE BATTERY" - is a message I get when clicking on the battery icon. Currently it's 100% charged and i get about 2 hours work from it. But it seems the battery might be failing too? (this is a message I got only after I upgraded to El Capitan, on Snow Leopad 14 days ago, there was no problem). QUESTIONS: What can be done?What are the causes of this overheating? Why does my fan not kick in more often? Can I somehow get it to work more, and would it provide a solution? Are the temperatures mentioned above normal? Is my hardware failing? I need badly to fix this; cannot visit any Genius bar anytime soon (live 2 hours drive away from a store) and do not have a warranty either. Please help. Thank you, kristina UPDATE!!!: After i covered partially the vents with the palm of my hand,the RPM of my FAN started spinning and the temperatures of CPU indicators went immediately down. And the system got "speedier" again. Could this be a problem of some sensor? If so, how to fix this? I actually now installed SMCfancontrol...and it seems it's taking care of business. But can this be a long-term solution?