I know this answer comes a bit late but since I got BD a couple of days ago (release dates in Greece kinda late) hope you forgive me.
Anyway the problem you mention seems to appear to many Radeon equiped PCs either desktop or laptop - Mine is an ACER Aspire 2000 ( Mobility Radeon 9200 ) with XP Home- so I worked on it and I came up with this solution :
-changed the smooth option in config.lcl (or sth like that) to 0
-changed windows color depth to 16bit
-closed every running app and proccess except system ones plus the following :
taskswitch , task manager and soundman .
After all this stuff the game ran as expected , hope it works for any of you who experiences the same problems.
