My computer fails to identify my WD 1tb external

I fixed that problem with a WDC My Book Home 1TB in Windows 7:

The drive was recognized in computer management and in device manager but no drive letter was allocated while connected with a e-sata cable.

1.in computer management > storage > disk management
2.rightclick drive 1 or wathever the number of the WDC drive (which should be basic at this time)
3.select 'convert to dynamic disk'
4.drive should get a drive letter
5.format (warning: all data get lost, but you can download original software from wdc.com)

Succes!
Olivier