Wa `alakum as-salam

There is a difference between singing without Music and Music. There is total unanimity amongst all scholars that if singing encourages bad behavior, extra-marital affairs, lewd behavior, skimpy clothing, drinking, or making fun of religion or people who are upright, it is totally prohibited. For Music and using musical instrument, it is completely prohibited. This means that by consensus of the scholars the vast majority of modern popular music (certainly, the likes of Britney Spears, Rihanna, Snoop Doggetc) is prohibited.

There’s also consensus that singing with simple drum is acceptable and there are evidences that this would occur at weddings and other celebrations during the time of Prophet (peace be upon him).
There are no explicit verses in Qur’an to prohibit Music, although some highly respected commentators, in particular Ibn Mas῾`ud says that “idle talk” in Quran  31:6 refers to Music.
However, there are explicit hadith that prohibit music. Melodious human voices and harmonies which are added to singing resemble musical instruments and a number of modern scholars maintained that they are prohibited. Their ruling is extended through analogy by comparing the effect made by musical instruments and those computerized harmonies which are basically produced through human voices.