Well, you will often hear and read the advise to not use a professional audio interface for playback of system sounds, because they might cause problems if using the device in a professional setup. Imagine for example your "pling" beeing blasted out of a PA, because you forgot to mute system sounds. And there are several other possible problems regarding system sounds.
Nevertheless it is possible to use most of these devices for system sounds and it works very well, at least for me.
So if you get pops and crackles using system sounds thats quite a different question. I'm a bit out of XP, but as far as I remember you can set the sampling rate in the sound settings of windows. Windows will then resample everything to the specified sampling rate.
Good luck...