My laptop cannot detect my sony mp3 player. each time i inserted it in, a flash of red light came on and then went dark.

The battery in the player is beyond its useful life and wont charge. Replace it.

It sounds like you have got rid of the software on your mp3 player which is why it isnt recognised. You say you formatted it rather than just deleting what you did not want. I take it that you formatted your mp3 rather than the computer? If you formatted the computer you may have drivers missing.

HI,
   Please find and press the reset button, trying to attach pic but not doing, Any way find reset button in the hole at back og the player. insert some thing in the hole and press the reset and your player work fine again.

Thanks for using fixya.

Try formatting the laptop and insert it. it worked for me.

go to settings/player/theme-change to peace or something bright- that may help.

Be sure its blinking 5 times, count after it cycles the first time through the red lights. If it is fact 5 times, that is a lamp driver error.More likely it cycled 4 times, which is common on this model, if that's the case, then it's the fan. Most likely the large one in the rear...It's an easy fix, just pull the back off and replace the part.

Charging the Player
The player needs to be charged before it can be used and every time
the battery gets low. It takes approximately 2.5 hours to charge the
Player. Once fully charged, the Player lasts approximately 8 hours.
To charge the Player:
Remove the USB cover on the Player.
Connect the Player to the PC using the Flash Plug.
The Player will begin charging. The battery indicator should begin
to flash, alternating red and green.
Once the battery is fully charged, the indicator light will stay red.
Note: If this is the first time the Player is connected, wait until
Windows detects the Player and follow the prompts to install it.

On opening my pen drive it displays "Pl insert a disk in drive G

I believe this is answered already. Turn the hold button on. Red light will be on. Hold the rewind button while you insert it into the computer. Please search online this has been answered. I am recalling from what I read a few minutes ago.

Try reinstalling your usb ports.

1. goto desktop, right click on my computer and press manage.
2. goto the device manager, find the usb devices / ports.
3. Make sure you are useing a ps2 mouse / keyboard since if your mouse/keyboard is connected to usb they will stop working untill your pc is restarted and the devices are reinstalled.
4. Uninstall all usb devices.
5. after all usb devices are uninstalled reboot the pc.

If the problem is with your drivers ( your pc detects the mp3 player but no drivers found) Download the newest drivers for your product and operateing system from the vendors website.