disabling msn (W98)

[engin]

Hi there,
i have small problem,my network contain 1 windows2000 advanced server & 60 win98 client which is usually used in the lab. the teachers complains that many student useing msn messenger and yahoo messenger.
any body know any solution that disable these services (msn&yahoo messenger)

**Note : all the computers in the network connecting to the internet through a sisco router and had public real ips.
thanks

[DanK]

Double posted, also in Windows 95, 98 and Me Security</font color=red> (http://www.winguides.com/forums/showthreaded.php?Cat=&Board=secwin&Number=72471&Search=true&Forum=All_Forums&Words=engin&Match=Username&Searchpage=0&Limit=25&Old=allposts&Main=72471><font) forum


<font color=green>Dan</font color=green> /images/forums/icons/smile.gif
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