I have a nexus 5 that give me a Black screen when i unlock it with sign-code.I can't utilize it but i have to recovery my data.I thought to install an update image with adb sideload to see if my phone restarts to work well and recover my data but I don't know if the update images wipe my data.Do update images wipe my data.Are there other methods to recover my data?
Sounds like your launcher (home screen) is acting up. Turn on USB Debugging if you haven't (go to Settings from the notification bar), then
adb install another launcher from your PC. After that press HOME and select what's installed.
Don't try updating stuff yet - there are ways to recover even if the above fails (though more complicated).