i just learned from my classmate a little trick i want to share with all my friends here. i was running VirtualBox on my laptop. i had a guest OS with CentOS. but for some reason after two days of using the virtualbox, my laptop started to use high CPU. im running windows 7 and on the task manager i can see the virtual box was at the top. the cooling fas was going off. i started to get worry because this was not normal on my HP laptop.

so to fix this, simply create a dummy guess with minimal memory and disk space, for example, i setup mine with 5MB of memory and 100MB of disk space. that it, after i started to run the dummy virtualbox and my other CentOS server, the CPU when down dramatically. i dont know if this is a bug in VirtualBox. but it works!!! try it