Hi @Shazia1, let me see if I can help out here!
In order to reset your phone using a computer, I suggest that you try to repair the software using Xperia Companion. Please note that since the device cannot pass the boot screen, you need to start the repair without the phone plugged in and make sure to tick the box in the bottom left corner "My device cannot be detected or started, or is a Smartwatch 3" and then click on "Next". After this you should be able to follow the on screen instructions given by Xperia Companion.
Try this and let me know how it goes! 
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