Game crashes when trying to load a saved game

I have an annoying problem - sometimes, but not always, game crashes when i´m trying to load a previously saved game and I get this message: "DRIVER_IRQL_NOT_LESS_OR_EQUAL" and I have to reboot my computer.

I´ve tried to open previous savegamefiles or autosaves from the same game, but they won't ever open, so I have to start a completely new game and try to finish it without saving (which is hard, ´cause I also have to work, sleep and spend some time with my family) or save the game when I'm tired enough and hope I can open the save-file the next day.

IF I can open the save -file, I can also open previos saves from the same game, as well as autosave-files.

I have vanilla civ4 with the newest (1.7*) patch. I had the same problem already with the earlier (1.61) patch.

Can somebody help or explain the phenomenon?

By any chance do you use Windows XP?

Yes, XP it is.
I didn´t have this problem earlier, but something seems to be corrupted somewhere (or there is something rotten in Win Xp)

Never mind. I just got BtS as birthday present from my wife (who also likes the game). I installed it and now everything works perfectly again.

Can somebody give me some extra hours in my life