Unable to open an item with a single click in Windows Vista Business

Solution:

1) Click 'Start' and click 'Control Panel'. (The 'Control Panel' window appears.)

2) Click 'Appearance and Personalization'. (The 'Appearance and Personalization' window appears.)

3) Click 'Folder Options'. (The 'Folder Options' dialog box appears.)

4) In the 'General' tab, from the 'Click items as follows' section, select the 'Single-click to open an item (point to select)' option.
5) Click 'OK'.