OK

I downloaded win32diskimager-v0.7-binary.zip and 2012-12-16-wheezy-raspbian.zip. after unzipping the diskimaging file I had Win32DiskImager.exe. I used this to write to the SD card.

My green light flashes once only. then nothing.

I have the same issue. My SD card is a Sandisk ultra 30MB/s -10, 16 GB. I have also tried a Sandisk ultra 30MB/s-6,16Gb and a San Disk 4GB-4.

Plug in, red light comes on, green light flashes once.