Method 1: Verify your clicking method
Make sure that you are performing a true single physical click. A single-click occurs when you press and release a mouse button one time.
Method 2: Test the mouse in multiple programs
Close all programs and test for the problem on the desktop and in other components of Microsoft Windows, such as Control Panel or Microsoft Windows Explorer.
If the problem only occurs in a particular program, troubleshoot that program. The program is most likely customizing the mouse commands.
Method 3: Test the mouse in safe mode
To start Windows XP in safe mode, follow these steps:
1. Click Start, click Shut Down, and then click Shut Down in the drop-down list.
2. In the Shut Down Windows dialog box, click Restart, and then click OK.
3. When you receive the following message, press the F8 key:
Please select the operating system to start
4. Use the arrow keys to select the appropriate safe mode option, and then press ENTER.
5. If you have a dual-boot or multiple-boot system, select the installation that you have to access by using the arrow keys, and then press ENTER.
6. Test the mouse.
7. To leave safe mode, restart the computer and let it start in Normal mode.
If the problem does not occur in Safe mode, there is a software anomaly; go to method 4.
Method 4: Troubleshoot your software
Check your mouse properties settings in Microsoft Windows
Make sure that Double-click or ClickSaver is not enabled. To do this, follow these steps:
1. Open the Mouse Properties dialog box. To do this in Windows XP, click Start, click Run, type main.cpl, and then click OK.
2. Use the appropriate method for your version of IntelliPoint software.
Version 2.2 or earlier:
On the StepSavers tab, click to clear the ClickSaver check box.
Version 3.0 or a later version:
On the Buttons tab, under Button Assignment, make sure that the Left button setting is Click (default), and not Double-click.
Microsoft has addressed this problem. It is not common, but it happens. Here is the support page: http://support.microsoft.com/kb/266738