Try flash mode on phone : keep pressing 9 key while starting the phone. (normal result is white big display and red "download" on external display).
Then plug the usb cable and see if Pc detects it.
Good luck.
I have another Z500 in DOWNLOAD mode and haven't right flashing cable, my question is -> how can i restore back from DOWNLOAD to NORMAL MODE, can anybody help me?
LOL
i'm working 10years among the mobile phones and first, what i can do, taking the battery out and put it back, but the DOWNLOAD MODE is PERMANENTLY, therefore my question about restoring to NORMAL MODE.
full flash the phone (usb_boot) included, when flashed ok downloader will notify everything is ok, remove usb cable, power on the phone and download mode is gone,