[Q] W7 wont recognise phone when in fasboot mode topic

I've been struggling for a week with this.
Trying to unlock the bootloader but whenever I get to the stage of using command prompt I get this message;

'fastboot' is not recognized as an internal or external command,
operable program or batch file

The PC just will not recognise the phone when in fastboot mode although it does when not.

Windows 7
Android 4.3
HTC Sense Version 5.5
Software number 3.62.401.1
HTC SDK API Level 5.65
USB Debugging ticked
Fast boot deticked
HTC cable used
Latest drivers installed

Any help would be appreciated, the only previous experince I have is rooting a Galaxy note and tablet with no trouble whatsoever.
tj