Whenever I run a CPU-heavy activity (like compressing a big set of files into an archive for example) my CPU switches to its full throttle (maximum frequency) and shuts down of overheat in less than a minute.

Instead, I would like it to keep slowed-down slightly to do the task a bit slower but be able to reach the finish.

At the same time I don't want to dim my screen brightness or adjust anything else what standard Windows power-saving system does.

So how do I actually set a cap to limit my CPU power?

The CPU is Core 2 Duo T7250, the OS is Windows 7 32-bit, there seem to be no BIOS settings or jumpers available to configure the frequencies.