F17 - problem with overheating

[Paolo De Michele]

hi all,

I've installed F17 on my laptop Sony VPCEB4C4E 32bit (KDE)
I noticed that very hot without doing anything complex; the fan runs like 
crazy -

I opened the laptop to see if there was dust on the cpu fan but it is clean
I noticed that maybe when I watch a video, I look at the mail (thunderbird, 
kmail) or do a bit of multitasking then the fan runs a lot (the cpu never 
reaches 100%)

what can be the problem?
thanks in advance
cheers