SD card problem

I cannot setup my SD card with the necessary the necessary op system. I have tried using all the techniques described in http://elinux.org/RPi_Easy_SD_Card_Setup.
SD card: Transcend SDHC Class 6 4GB
Computer OS: Vista

In using Win32DiskImager and fedora-arm.. the main problem seems to be that nothing appears when I click the Device button (I run both as 'administrator').
Using flashnul the process appears to complete but the SD card won't open in Windows Explorer when I try to check the contents - on checking the properties the card is full.

I've used SDformatter to reformat the card and tested the card in the Pi with no response. The card works fine if I copy files to it.
None of the suggestions that I've found on the wiki appear to work.

Really appreciate any advice

You won't be able to see the Linux partition under Windows. you should be able to see the small FAT partition with a few files in it.
My Main comment though is why are you attempting to use Fedora?

I just went through the same problem. The bottom line is that win32diskimager does not work on some sd card readers in some computers. You either need to use an external card reader or a different computer.