Oracle sudden, inordinate irrensponsibility and ORA-07445

if you ever experience sudden, inordinate irrensponsibility of your oracle instance (one or more threads are running at 100% cpu) and find an error message like this in your alert.log:

ORA-07445: Exception aufgetreten: CORE Dump [ACCESS_VIOLATION] [unable_to_trans_pc] [PC:0x7C921766] [ADDR:0x4C43414F] [UNABLE_TO_READ] []

this windows xp sp2 hotfix may be for you:

KB951312 – When you run an application that uses a timer queue on a Windows XP-based computer, the application may stop responding