Cpu downclocking

I have MSI fx600 laptop with core i5 460m processor. Since i bought it, on full load CPU temperatures reach 100C! And battery life time is rubish, so, i thought would it help if i would downgrade cpu clock speed, or voltage by a bit? Also, mayeb you know guys, is it possible to just disable one of the cores (my cpu is dual core with HT) when i want to? I mean, is it possible wihout restarting windows to do that?

Oh and by the way, feel free to give me some tips how to expand my laptop battery life time (because I get max of 3,2hours (its normal for this laptop, not for me :))

Thanks for your time :)

Thanks for the responses.
I think my laptop heatsinks are very clean, since most of the time it stands on the table. I dont know the condition of thermal paste, because due to waranty stuff, they wont let me open my laptop without breaking waranty rules (which means - if you open laptop - goodbye waranty).
About cooling pad, yes, it is very effective yet it is not a solution for my situation. Still, thanks for these tips.
SlasherIT - thanks, but NHC undervolting program is only available for 32bit OS users. Currently I am using 64bit windows 7 ultimate. And no, compatibility modes does not help.

SlasherIT said:

Sorry, forgot to check... There is an unofficial 64 bit dll... I haven't tested it, will make a tutorial when I do. Heatsinks fill with dust fast... Since you're still on warranty tell Dell to check the hardware...

Dell? You mean MSI?
Anyway, I actually found pretty good undervolting guide. If anyone needs it, it is here: The "Undervolting" Guide

SlasherIT said:

Ya MSI lol. I already have that guide... I was actually referring to that guide. RMClock doesn't work with the Core i series or 64 bit systems, although there is an un-official patch for it to run on 64 bit... sorry.

Slasher

Yes, as it turns out during the time when program was developing, no i series CPU's were developed.
So thats why I am still looking forward to hearing from you guys for some tips how to undervolt my cpu.