Have just purchased a Nikon Coolpix S3000/ Bought a SanDisk 2gb memory card whch will not work just says 'write protected'. Have looked for a switch on side to unlock but there doesnt appear to be one. Is this a problem with the card or camera

There is a Lock switch on the left side of the SD card. Make sure the Lock switch is slid up (unlock position). You will not be able to modify or delete the contents on the memory card if it is locked.

Remove the memory card from the camera, look along the one edge for a switch, slide it toward the contacts to unlock. The switch that is farthest from the contacts is in the locked position, slide it back and forth to reset. If that fails replace the card.

The write protection is initiated by your camera, not the lock switch on the side of the card. Check your manual for the procedure to cancel write protection.

Sandisc makes cards in various speeds or "classes". For videos, it's best to use a class 6 or better card. Sounds like your new 8GB card is a class 4 or lower.

Take the memory card out of the camera and look at it. SD and SDHC cards have a slide switch along one edge. The position farthest from the contacts locks the card, protecting it from writes. The position nearest the contacts unlocks the card. If the switch is already in the proper position, slide it fully the other way and then back again.

The S3000 will use any SD or SDHC card. SD cards max out at 2GB, SDHC cards at 32GB. Don't worry too much about speed, though a faster card may download faster if you use a real card reader instead of using the camera as a card reader. You can use any major brand.

The S200 uses SD cards. Your new 4GB card is actually an SDHC card and will not work in the S200. You need to use SD cards, 2GB and smaller.

the camera's detector may be broken

4GB requires FAT32. Camera firmware only supports FAT16. 4GB won't work because FAT16 has a 2GB maximum size limitation. 1GB CF card is Nikon's "approved" maximum for this camera.

Catch: 22 1GB -and lesser capacity- CF cards are no longer manufacturered or generally available in 2010. When the current CF card dies, the still working camera also becomes throwaway unless you can source a CF card 1GB or under. 2GB may work, but with 'issues' per caution below.

CAUTION: Anecdotal evidence suggests the final release -& current- firmware for cameras of this generation is also encumbered by with a maximum picture number limitation of 999, realistic at the time of original manufacture when 256MB was a the largest capacity CF card but completely nonsensical now.

Summary: This is my first NIkon Digital camera and also my last.

Apart from the noteriety of the ubiquitous broken Nikon plastic battery latch, a major design flaw Nikon refuse to acknowledge or accept liability to rectify -since self-repaired better than OEM, Nikon policy on firmware support is complete abandonment of product within an unacceptably short service window. ie: a deliberate poilicy of enforced obsolescence.

Suggested Problem Remedy: Do buy a new camera supporting SD Cards of current capacities. Don't buy anything branded Nikon.

Not sure if this helps, but it worked for me on a Coolpix 5000.
I tried a 4Gb card, and the camera formatted it and reported out-of-memory. The problem seams to be that that max 2Gb is supported

What I did was partitioned the card into 2 sections with 2Gb on each. I then formated them to FA16.
This worked - but you can only use half of the card (i.e. 2Gb)

For the tools I used a Linux laptop with CF reader. The tools are build in here (fdisk and mkdosfat). I don't know how to do it on windows.