05-21-2013 05:13 PM - edited 05-21-2013 05:14 PM
Hi and Welcome to the Community!
"Why" is a rather challenging question to answer at an internet-distance. It could be software/OS, or it could be hardware defect (which of course cannot be diagnosed at an internet-distance). Also, "faulty" provides very little description from which to make any useful guesses. Nevertheless...
Anytime random strange behavior or sluggishness shows up, the first thing to try is a proper reboot:
See if things have returned to good operation. Like all computing devices, BB's suffer from memory leaks and such...with a hard reboot being the best cure.
05-22-2013 11:50 AM
OK...then next I recommend that you attempt to boot into Safe Mode:
It may take you multiple attempts to get the ESC key sequence (press/release/hold) correct, so be patient. When successfully into Safe Mode, see what happens.
If the behavior ceases, then think carefully...what happened just before this behavior started? A new app? An update? A Theme? Something else? Think carefully as the smallest change could be causal...and attempt to undo whatever that was.
But if the behavior continues in Safe Mode, then you may need to consider more drastic actions -- WIPE, OS Reload, BBSAK Wipe/Reload, and the "Bare Bones" OS Reload Process. To prepare, you should be sure that you have a full backup to your PC...please review the Backup link in my auto-sig on this post for instructions.
You may also need the use of these tricks:
Also please consider that, at an internet distance, it will be impossible to actually diagnose your issue if it is truly hardware related (e.g., defect, damage, etc.). Rather, all we can do is provide you processes (sometimes quite tedious!) to conduct to try and rule various things in or out; if none are causal, then the deduction becomes hardware. But we can only do that as a deductive process. Further, no amount of OS or software fixes we can give you will be of any use if indeed the issue is hardware...only a qualified BB technician, with the device in their hands, can actually give you a proper diagnosis (and estimate) if the issue indeed is hardware.
Good luck and let us know how you would like to proceed!