Using VirtualBox-How printscreen since shortcuts are deactivated?

Hello,

I am using VirtualBox to have also Windows XP at my mac. I use some applications that run only at Windows.
So, I've come across this problem. When logged in Windows, the stortcuts of Mac don't work, because it's switched.

Hence ,how can I printscreen within Windows and Open the task Manager with Ctrl+Alt+Del ?

I can face the first problem temporarily with print screen through mac , copying the file to Dropbox and get it through there, to edit it in Windows. But what about the second?

If you have encountered the same problem, please let me know, I will also ask at VitualBox.org

Thank you in advance !