How to prevent windows from locking / sleeping (without admin privileges)

Solution 1:

You can download and run this little program: No Sleep

Get it from here

No Sleep - Cnet

No Sleep - Apponic

It moves your mouse once a minute by one pixel. Thus it prevents your windows from going to sleep mode.

Solution 2:

You could use this AutoHotkey script:

CoordMode, Mouse, Screen
Loop
{
    ; Move mouse
    MouseMove, 1, 1, 0, R
    ; Replace mouse to its original location
    MouseMove, -1, -1, 0, R
    ; Wait before moving the mouse again
    Sleep, 600000
}
return

You can download the portable version of AutoHotkey here.