Well I finally found out it was the ATI IGP 320M chipset that was in my Compaq Presario 2100 laptop computer.
And after quite a bit of searching, I found the ATITool at this location http://www.techpowerup.com/atitool/
, which allow some tweaks to core voltage and core frequenzy. But sliding the Core slider did not seem to have any effect.
Also there was the "Central Brain Identifier" where I was able to set a lower multiplier, but not a multiplier higher than 13.5 which is the "normal" mulltiplier, and changing the core voltage from 1.45V to 1.5V immediately froze the computer.