CPU Fan Speed Registry Hack??

[dx100-uk]

hi All
since i loaded IE7 & its assoc hotfixes etc
my CPU fan goes flatout all the time after windows has started, it does not do this until someone has logged in though!
i rolled back the installs - still does it.

sadly i have a motherboard the does not spt fanspeed/speedfan etc progs (no sensors are detected - though AiDA32/everest does show speed)
the dreaded Compaq presario cutdown K8S-LA with SiS760GX chipset

also i cannot change it in the bios - not there! nor find any bios upgrades etc bloody board!

i am now thinking down the lines of a there must be a reg value to control this
---any ideas where

else i will just have to rewire the fan to the 5VDC line as a last resort.

anyone elses thoughts welcome

dx100uk