See tip 302 before you bother with this hack.
1.Edit HKEY_CURRENT_USER\Software\Microsoft\Windows
NT\CurrentVersion\Windows
2. Select the Programs value and then choose String from the Edit
menu.
3. Add the 'scr' extension to the string as follows: Programs:
REG_SZ: exe com bat pif cmd scr
4. Choose OK, close the Registry editor, and log off.
5. Log back on and from Explorer, highlight the screen saver you
want and right click to define a shortcut.
Example:\WINNT\SYSTEM32\SSBEZIER.SCR /S
The /S switch forces the screen saver to start immediately. Remove the /S to display a setup screen. You can not use a screensaver that uses a password.
Never use anything other than the blank screen saver (scrnsave.scr) on a "Server" as it will steal needed cycles!