This would effectively leave you unprotected, which sort of begs the question, why would you want to do this?
If you can let us know the reason, then perhaps we can be of more help and offer a suggestion.
Hi! sorry for the late reply..

my reasons are simple, first
(correct me if Im wrong) it is not advisable to run two or more anti-virus resident scanner at the same time.. second the other anti-virus Im using is password locked
(I cant uninstall nor unload, but I can disable the startup) by the administrators who installed me original licensed copy from my school
(this is Trend OfficeScan "CORPORATE EDITION" built specifically for server-client setting) third I prefer to just use one resident scanner which is Trend's OfficeScan instead
(eventhough I think this AV is not that good...) and fourth Im thinking
(correct me if Im wrong) having two or more anti-virus installed and use them all on separate scanning routine is not bad.
I would also like to ask, if it is "OK" to turn the avast entries on the services tab of the msconfig (services.msc) to manual? What would be the effect? I tested avast and run it while the services entries are manual, avast succesfully detected eicar virus test file.. what about other effects of turning the services entries to manual?

Thanks for the replies!