I left my Sansa Clip MP3 Player plugged in while putting my laptop into hibernation. Now player does not response, I can't turn it on, and laptop doesn't recognize it at all.

You can try and reset the player. resetting a Clip player: 1. Slide and hold the Power switch up for approximately 20 seconds. 2. Release the Power switch. 3. To turn the player on, slide the Power switch up then release instantly.
Some things to check for when your player does not act like its taking a charge.
USB Cable Make sure that the USB cable is properly plugged in and use the original cable that came with your player.
Computer in Hibernation mode Make sure the computer isn't entering hibernation or sleep mode while the device is connected. The computer must be ON in order to charge your player.
USB Port 2.0 Make sure the player is connected to a USB 2.0 port (1.1 occasionally causes charging problems).
USB Port location Try plugging into different USB ports (i.e. USB port in the back of the computer); occasionally the front USB ports have limited power to charge up the device.
Battery Make sure the battery is fully charged. It takes approximately 3 hours to fully charge the battery.
Latest firmware Depending on what Sansa player you have, make sure it's up to date with the latest firmware.
AC charger (optional) AC chargers (sold separately) have a 500-1000 milliamp max output, which provides much better charging ability than a USB port.
I have some tips posted here on MP3 players and their problems. Connection problems MP3 player not found by computer
SanDisk Mp3 Player Frozen

1. First, you have songs saving in your computer.
2. You have 2 ways to put music on the Sandisk Sansa Clip:
2.1. Plug device into computer, Drag and Drop music from your computer into "Music" folder of the Sandisk Sansa Clip.
2.2. Use Windows Media Player in your computer to transfer songs to your device; Plug device to computer, open Windows Media Player, click on Sync tab, drag and drop music into "Drag items here " on the right side of the windows media player, click on Start Sync button.
Good luck

This is direct from the sansa FAQs at http://www.sansa.com/support/sansa_clip/faqs 02. Why won’t my Sansa Clip charge when I connect it to my computer? USB Cable
Make sure that the USB cable is properly plugged in and use the original cable.

Computer in Hibernation mode
Make sure that the computer isn’t entering hibernate or sleep mode while the device is connected. The computer must be on in order to charge your player.

USB Port 2.0
Make sure your player is connected USB 2.0 port (1.1 occasionally causes charging problems).

USB Port location
Try plugging in different USB port (i.e. USB port in the back of the computer); sometimes the front USB ports have problem charging up the device.

Battery
Make sure the battery is fully charged. It takes approximately 3 hours to fully charge the battery.

Latest firmware
Make sure to update firmware by downloading and installing the Sansa Firmware Updater.

I hope this helps, and don't forget to rate the answer.

go to control panel and click on portable media devices note:will not work on windows xp even if you downgrade to classic using a disk

Hi, just had the same problem after restoring my system.

You must disconnect and update your Windows Media Player to Number 11. My reinstall left me at WMP 9 and it wouldn't recognise my Clip. Go to the Windows website, follow the download instructions, and you should be fine. When you plug in the Sansa Clip or MP3, it should recognise it right away. Hope this helps!

The Sansa Clip - US Version is the only one of the Sansa players not to have a firmware upgrade that adds correctsupport for Hebrew. I hope your player is Israeli. If it is:
Menu --> Settings --> Language --> Hebrew
(p. 19 of your user manual)

On the Clip, they had no right-to-left vs. left-to-right swapping functionality even with the firmware upgrade, I believe.

-Tha Mp3 Doctor

Reformat clip with disk utility after looking at it like an external disk. Do this by turning it off. Puting it in lock mode. Hold down middle button as you plug it in.

I am mad at my Clip as it did the same thing.

Screen shot here:
Sansa clip not recognized.

put it on the hold position and press down the middle button while you plug it in the computer

Unplug mp3 player from computer. Uninstall all the Sansa software. Then reinstall it. Then and only then, plug the Sansa back into the computer.

Put the Clip into hold (left-side switch down!) and press the center button down while connecting the USB cable