power point warning message

[sushant likhar]

when a power point presentation is open we get the following warning.
"Some Files may contain Virus or other wise be harmful to computer . You
should be certain that this file is from trustworthy source.would you like to
open this file"

We were not getting this message initial . Today there was a hot fix on
window and we got this popup message on all this machine.

Any help will be greatly appreciated.

Thanks
Sushant