BUZZ
ok i'm assuming you editted your GameData.dll? (or have an editted one)
this happened to me, and it took me a second to realize why. if you edit your software... it'll change (duh me)... anywho the clock goes away if you change the version of the software (i.e. from English to Snglish) i am unaware of a way to revive the clock... but i hope this clears up the mystery
EDIT: it may occur with macros (and any editted client, perhaps)