Under Vista the task manager feature is not automatically launched upon pressing ALT+CTRL+DEL. Results: you shall get a splash screen with various options, from which you must select the desired option. The process is as lenghty as the text I've written above! ..
Still there's a way to access the Task manager more rapidly, you can create a desktop shortcut, here's how:Right Click on an empty area of the Desktop>Select New>Shorcut
Enter the following path (location of the item):
Click on Next
You can give a custom name to the shortcut or leave it as "taskmgr".
Click on the finish button and it should be OK.
Note that: you can still use the "taskmgr" command in the Run tab or the Windows search bar for quicker access!