The best way to recover deleted photos from android phones like htc hd7 is to use some android phone photo recovery guide, here's a good one recover deleted photos from android phones hope this helps you get back deleted photos from your htc phone.
To check your memory card ,you need a memory card reader.
insert your memory card into the reader and connect the reader to the USB of your PC. save your data if needed.
if its reading try to format it in your Pc by right clicking the mouse.
format option. then insert the MMC back to the phone and format it in the settings menu/storage.
your memory card will work fine.
if you cannot format using your PC replace the memory card.
It somehow need to update the phone with the same firmware,many issue regarding this problem,but give this thing a try,might be your luck day.
To start up with,
* Turn off the phone.(be sure battery is fully charge)
* simultaneously press volume up and down then press power ON.
* a message comes out,simply follow instruction,you may release the volumes now then press down volume key to proceed with the hard reset(camera button will be the enter key) .just wait the process until the phone reboot.DONE
Here's a video so you can visualize the procedure.
There are two ways to turn off emergency
1.You mobile phone receives weak signal from near tower so try to Switch off your mobile,wait few seconds and switch on.
2.Your mobile is locked to particular network provider.
If your problem persists after switch on your phone means definitely your mobile phone is restricted by some network so try to unlock your mobile phone.You can unlock your mobile phone using network unlock code.It's the best way to unlock your phone.If you need an unlock code for your HTC HD7 phone visit MobileUnlockSolutions.com I hope it will be very useful to you.