Slow and unsteady

Im new to this community so please forgive me if i am posting this in the wrong area. I know that these things can become a little territorial so please let me know if this thread would be better posted in another place. 

I upgraded to teh new firmware this week and since then its been very temperamental.  Sometimes it freezes and refuses to play a video file and someyimes it doesnt recognise my external HD when i plug it in to the usb in the front.

Any help would be appreciated.

i have a wd hd tv live hub by the way.

now it freezes everytime i plug in my external hard drive, something it has never done before, it then refuses to move for 10 mins.

help please