cpu speed problem

[fedora]

Hi listers

here is a laptop with

[root at myhost ~]# cat /etc/fedora-release
Fedora release 7 (Moonshine)
[root at myhost ~]#

worked well until 10 days ago. then, the laptop started its fan, and 
drove down its cpuspeed to about a quarter of the speed before. if i run 
the system-monitor, the cpu is busy always about 30 %, whereas before it 
was busy only about 6 %.
The fan from then on is never stopped and the CPU stays low in 
performance from then on. i have to do a power down (either pm-hibernate 
or halt/reboot) in order to make it come up with the "full" performance 
and stay there for a while. after that, the fan starts again and the cpu 
slows down.

after some googling i tried the following:

[root at myhost ~]# cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq
997500
[root at myhost ~]# cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_cur_freq
731500
[root at myhost ~]# echo "997500" 
 >/sys/devices/system/cpu/cpu0/cpufreq/scaling_setspeed
[root at myhost ~]# cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_cur_freq
997500
[root at myhost ~]#

i also changed the parameters of the cpuspeed program, so that now it 
comes up with:

  1413 ?        Ss     0:01 cpuspeed -d -p 90 45 -m 731500 -M 997500 -n

all to no avail.

i also checked to see, whether in the BIOS the intelCPUstepping is 
enabled, and it is enabled.

i understand, that the fan at a certain point in time starts turning. 
but i don't understand, why at the same time, the cpu slows down.

has anyone got an idea, where this immediate change stems from and how i 
could stop it?

thanks in advance for any reply

suomi