Just in case sombody else has seen this.
(Has happend up to now about 5 times in 2 Months Win XP)
Window pops up with
"drwtsn32.exe - Entry Point Not Found"
Then you can click ok and the window disappear and also the Fancontrol.exe process is lost.
-> Can be a problem when the fan is currently off while this happends...
I've made a little Autoit Script which checks if fancontrol.exe exists and the error message does not exists.
In case the error exists then it clicks automatically ok and restarts fancontrol.
As this is only working if you are logged in.
I also shut down fancontrol.exe in case I lock the screen.
(As I doesn't care about the fan noise if I am not next to the laptop)