You can use the ClickLock feature in Windows 7 if you have trouble holding down the left mouse button and moving the mouse at the same time — a common problem for notebook users. When you use the Windows ClickLock feature, you can tell Windows how long you want to hold the mouse button down before Windows locks it down.
This feature allows you to hold the mouse button for a few seconds, move the mouse to the new location, and then click it again. The effect is the same as a drag and drop but without having to hold the mouse button for a long time
Click Start. Type mouse and press Enter.
Windows opens the Mouse Properties dialog box.
Check the Turn On ClickLock box and click the Settings button.
Set how long you want to hold the mouse button down before ClickLock kicks in.
Click OK.
The changes take place immediately.