This happened to me right after I installed SP2

The installation of SP2 really messed with my video drivers as well but I removed and reinstalled those with the same results.
I uninstalled WB and reinstalled the non beta version and all is well now.
If this helps to remedy the problem my specs are
WinXP SP2
P4 3.2 Ghz
1 Gig Ram
Nvidia Geforce 6800GT 256 Meg 61.77 drivers