Music videos on DVD

Ive frantically been burning my 3 music videos onto DVD+RW and after several fails and weeks of changing conversion i have finally been able to playback on my Sony 890 DVDR,now its still not letting me edit or add any more videos on the DVD+RW as its finalizing on my PC after burning.Is there anyway i can get around this frustrating process of having only 3 vids on 1 disc or is it just im using the wrong dvd.I have even tried a CD-R as i was told music videos play on these. Please Help