On-the-fly underclocking an AMD Athlon 1,1 GHz Thu

Hi!

When I have the money for it, I'll just buy a better CPU-cooler, but until that time, would anyone know if it is possible to underclock my CPU on-the-fly? Like some tool that lives in my systray and detects that I only need 500 MHz to play some mp3's and surf the web?

The computer I own is second-hand, I bought it about 2 months ago. I tend to work all night, but my girlfriend needs her sleep. And the CPU's cooler makes a s***-load of noise! So any suggestions, except "Get yourself a new cooler!"?!

Thanks in advance!

ps. This is what Aida32 says about my hardware, don't really know if all of it is needed, but here goes:

CPU:

CPU Type	AMD Athlon-PECM, 1400 MHz (5.25 x 267)
CPU Alias	Thunderbird
CPU Stepping	A9
L1 Code Cache	64 KB
L1 Data Cache	64 KB
L2 Cache	256 KB (On-Die, Full-Speed)

Motherboard Name: MSI K7T266 Pro (MS-6380) / MS-6380LE