Removing vocals is at best, hit and miss. Sometimes it works pretty good and others not well at all. Just depends on the way a song was recorded as George stated. If you're wanting more than vocals removed, that is going to be even more hit and miss.
I would suggest trying to find the tracks you want in midi format. There are alot of options there and some midi sites offer custom songs for an affordable price. One such site is
www.midi-hits.com
Hope this helps,
Wally
