Anybody Upgrade CPU on Laptop?

[MegalosSkylaki]

Have a 5-year old Toshiba Sattilite widescreen lappy with 1.6Mz pentiumM Centrino platform.
neads a reinstall and have all dics..
Near perfect new condition, because left in CA and used 3 lb Dell latitude instead.

Question: what are chances and procedure for upgrading to , say, 2.0 mhz pentiumM CPU ?
Yeah, will run down battery faster, but being 15+", is not intended to run off battery.
Heat --and BIOS --probably the problem.

Any thoughts??

MegalosSkylaki