How can i remove hard disk from intel dot station i want to reinstall the system. My extranl CD rom is not ditected by dot station. so i want to remove the hdd and install it in other sytem.

This will not be a wise decision ..cause every system has its own configuration and when you will put it back you will have problems detecting the hardware on this one ...What I suggest is to insert the disk anyway ...and try to restart ..go to bios ..and make the boot priority on the Cd if it is not already set ....and boot from cd ...
The idea is that even if you got a virus and affects your disk drive detection into windows..when you boot from the Cd ..the old windows has nothing to do with what is going on than ...and it will work ...Just try and see...anyway ..only if the Cd drive is damaged physically this will not work ..but if its driver is affected by a virus will work and the installation will go on normally ...
In case is not working ...than you can just open the unit ..and inside you will see that the Hdd is only kept in place by the screws at the sides...and it has the bus cable and the power ...Removing them ..and after that the screws(pay attention that it may have on both sides...) or some models have just a lever that its keeping it in place ......