Urgent help needed: files no longer play (stuck at loading arrow)

have a look at this…

http://community.wdc.com/t5/WD-TV-Live-1eneral-Discussions/SOLVED-WDTV-Live-8-TB-NAS-freezes-after-watching-not-able-to/td-p/173922/page/4

maybe uPnP on your network somewhere causing the WD to die.