For convenience on many laptops, the touchpad functions like (left) clicking a mouse. However, in Windows Explorer, a classic problem occurs. We can drag and drop folders by mistake into other folders--they can get lost that way, or mess up our carefully organized tree.
The solution is a distance, a threshold, before accepting a drag (of a clicked mouse). We don't want natural hand jitter (visible at small resolutions) or accidental motion (while clicking) to be interpreted as a request to drag graphical objects around. This problem is well known--and Windows has such a threshold. However, their default is 4 pixels!
Some people's jitter is greater than others' (viz. Parkinson's disease); the default may be way too small to avoid the problem for touchpads, too.
Using 40 pixels as the threshold, I first move past two folders (or files) in Windows Explorer. Then before releasing the mouse, I pull it back to wherever I want, even to the adjacent folder.
There are two settings: horizontal and vertical. I set both the same--the horizontal is important, too, to prevent inadvertent mouse drags.
DragHeight = "40"
DragWidth = "40"
Restart the computer for the change to take effect.
This setting allows windows also to be dragged conveniently. Drag a centimeter (half an inch) then back to your new, desired, fine location. The feeling is like a momentary slow response.
If you wish, you can use Microsoft's TweakUI (a free-of-charge Windows XP download) to set these.
You might enjoy playing with click-lock (on the mouse) for this problem, though it changes the user interface in a deep way, globally.
I wonder if someone in the leadership structure of Microsoft might be big enough to admit--to themselves--they are continuing a mistake (whether small or important) that occurred some time in the past but was correct at one time, the mistake caused by an increase in monitor resolution (as others have said), and respond to some users' cries for help by changing this 4-pixel default? Because the key difficulty is in admitting a mistake. Already they have enabled us to change our setting; it's merely avoiding a redecision about the default which is causing a problem in the wider world.
The current state on this issue seems one of drifting inertia and big-company self-insulation. (Some of their attitude about it is visible on their Developer Network.)
Disable Drag And Drop In Windows Explorer? (from Scot's Newsletter's Forum, editor of ComputerWorld)
Stop Windows copying files accidentally when Ctrl-click selecting (How-To Geek: more)
Prevent folder moving (see R. McCarty's answer)
Click lock (see S. Goodkin's answer)
Copyright (c) 2011 Mark D. Blackwell.