Windows live mail When I open mail on my computer it shows that it has been opened but then when I login with another computer it shows it as unopened

This program is used at my work but we're having issues with it...

When the web design company came and made changes to my website they added and setup Windows live Mail on all the computers we have but when I go onto my windows live mail account and open a piece of mail and it shows that it is unopened but then when I go to a different computer and login it shows the mail as unopened when it has been opened on a different computer previously.

This problem has started from the beginning, it's not something that has just started.

This is a big problem because when I open the mail I would like it too be seen so my workers don't go printing off copies when i've already done it or come into my office explaining something that i've already read.

Please Help,

Dominic.