Is your mouse pointer, also called the “cursor,” always disappearing from your screen? Not a problem. You can customize your pointer so you can find it in a snap.
In Win7
  1. Click the Start button , and then click Control Panel.
  2. Click Hardware and Sound, click Devices and Printers, and then click Mouse.
  3. In the Mouse Properties box, click the Pointer Options tab.
  4. Under Visibility, select the Show location of pointer when I press the CTRL key check box, and then click OK.
Note: After you complete these steps, just press the CTRL key whenever you need to find the pointer, and it will appear.

Others look here;
Who took my mouse pointer?