kernel task taking so much of CPU usage causing startup to slow down :(

I've been using my cousin's macbook pro and though I am not a mac user and only knows the absolute basics, it has been working fine til recently. At first I was using it with what I usually use, internet and messenger. I shut it down and went to sleep. The morning I tried to switch it on, it took super duper long. everything was super duper slow. I figured it was those programs that was clicked accidentally and weren't logged out properly so I signed out the user of the laptop which had my cousin's name. And it was fine and I was happy....for awhile cos today, when the laptop was switched on, the same thing happened only that if I log out the user, the problem won't go away. Fan keeps running. and everything is super slow. I tried the comman+option+p+r. and it didn't do anything. Add to that, my aunt keeps blaming us (my other cousin and I) that it's cos we use the laptop so often >.< and by often she means about 30 minutes-2 hours log time with about 4-5 hours intervals. so please anyone...help :S or else my aunt will keep blaming me T.T

Uh oh...that doesn't sound good. A laptop I had developed problems like that, the motherboard was going on it, same with a PC at work that is slow, it's power source is also going. Could be malware or a virus as well. I'd take it into a repair place and have them look at it.

With the fan running all the time, does the macbook get hot in spots to the touch. With both my laptop and notebook (and PC's but not as much) you need to clean them out. The fans will collect dust on them and will cause the units to get hot. Computers don't like heat, it will cause them to run slower or even shut down. I find portable units like laptops tend to collect dust more quickly because of their portability and compact sizes.

Your Aunt obviously knows nothing about computers.

I don't think that it's really a fan being dirty problem because it jumps start after the laptop having had about hours of rest. It's not hot at the bottom as well... I hope this gets fixed

I've not used Macs much. I take it you can't end this thing that eats the CPU and keep the Mac running normally? If you have an Event Viewer then try to find System Logs. It will alert you of any software errors the computer has. My Brothers PC began to start up very slowly a while ago. I checked the logs and something was up with the printer software. About 10 clicks later, the problem was solved. You haven't downloaded anything that you shouldn't have, have you? Or installed anything? It could be that.

yes, from what I read (or understood) kernel task is like a manager on all the essential (basic) tasks on the laptop. And I can't view (or don't know how to view) what tasks kernel task is managing. So can't pin point what is causing it. sigh. anyway, my cousin knows already that her PC's broken and she is fine with it but still sad.. At least she's not mad.