Cannot put iPhone on vibrate mode

Hello,
I want to put my iPhone on silent mode. But there is some problem. I cannot put it on vibrate mode as it rings instead of vibrating. It does not vibrate at all. when i m busy in meeting or something. Any suggestions?

Thank you in advance.

There is a switch on the left side of the phone above the volume rocker that is used to toggle the phone into silent mode. A red dot can be seen next to the switch when the phone is in silent mode. If it is visible that means your phone is on silent mode.

There is a small switch just above the volume control on the left hand side corner and below the corner. To turn off the ringer, simply flip this switch down towards the bottom of the phone. An onscreen icon showing a bell with a line through it will appear to confirm that the ringer is off. Turning off the ringer will put iphone one vibration mode. If iphone vibration mode is turned off, the phone will automatically go to silence mode.

The best way to fix this is to hold the Power button and the Home button for 15 seconds or so, basically hold them both until the Apple Logo reappears. If that doesn't work you should hold both buttons for around 30 seconds, doing this will put the handset into recovery mode. Connect to itunes when prompted. Then it will ask you to restore it to a current version. Do all the updates and try again.

a small switch just above the volume control on the left hand side corner and below the corner.

Thank you, thank you, thank you! I have no idea HOW it got turned off but was going NUTS trying to figure out why I had no ringtones, only vibrate!!!