Issue with the Lock Screen

[Rennan]

Today I finally got my stunning white Lumia 800, I love the little thing.. but it's showing a problem, an unusual one....
My touchscreen works like a charm, everywhere, except for the lock screen...
works absolutely everywhere, but I can't use the touchscreen and the capacitive buttons while the phone is locked, and, I can't unlock it also... So if I want to do anything with the handset, I have to restart it (by holding the lock button, can't slide down to turn off)... pretty annoying if you ask me..
My Lumia 800 has WP7 version 7.10.8107.79
Restoring factory defaults and hard reset didn't fix the issue...

Does anyone have any idea what is causing the problem? Can a system update fix it?

 

[pmhgeneral]

Try this: go to settings /lock+wallpaper and check if the screen time out is set. It may be set to never lock this may be the problem.
Good luck.

 

[pixeline]

Try sliding your finger from the middle of the screen instead of from the bottom.

pix

Tapatalk@Note

 

[Rennan]

Try this: go to settings /lock+wallpaper and check if the screen time out is set. It may be set to never lock this may be the problem.
Good luck.

Unfortunately, I don't have this option, I have the following options
30 seconds
1 minute
3 minutes
5 minutes

Any way to enable it?

 

[Rennan]

Here is an update for my ordeal...
I updated the phone through Zune yesterday, so I could get internet sharing and stuff
strangely enough.. when the phone asked to restart so it could apply the update, the lockscreen worked! But only once...if I tried again, no deal...
Also, I can't use the touchscreen and capacitive buttons during calls (so I can't end calls or access any option)...

To me this clearly looks like a software issue (I could be wrong), does anyone think that if I flash it (debrand it maybe) the issue will be fixed?

Also, sorry for the double post