If you press control alt and delete (in windows XP) and you get a task manager window without tabs, borders or means to close it then it is running in 'tiny footprint' mode. Why anyone would need such a mode in task manager is beyond me - it doesn't save much space at all and it's not as if you'd ever need this to be on-screen for a long period of time anyway.

To fix it, double-click on the top border of the window.

http://support.microsoft.com/default.aspx?scid=kb;EN-US;q314227