I have Msn 8.5 since December and it was working fine. But the last week, I noticed that I can't minimize the contact list window. Although, I can maximize or close it.

Notice: This happens only in the contact list window. The chat window is maximized, minimized and closed with no problem.

Any suggestions? 

does it minimize if you press winkey+d ?

Which button is winkey?

the one between your ctrl and alt (the one with the windowslogo)

It is like closing because it is not displayed on the bar as an open window

hmm xp or vista?

edit: try winkey+M see what happens then...

the winkey+d works for me in vista and i guess it works in xp too

Xp. When i tried "winkey + d" in the chat window it minimized and was displayed on the bar as it was open. So why the contact list closes?

Well winkey+d minimizes all windows and after that it places desktop on top.
So it shouldn't close the contactlist.
If you press win+m it should only minimize try that and see if it closes then...

I did it and it didn't work.The window stayed where it was. It just became non-active so I click on it to become active again.

you using the messenger enhancer script? try disabling it

I have fixed it now. I think it was the Messenger Enhancer. You are right.