What is the ruling on one who was negligent in prayer for years and does not know the number of missed prayers, and is unable to make up for what she missed?

Scholars differed concerning making up intentionally missed prayers. The majority opinion is that making them up is obligatory, based on an analogy with one who sleeps through prayer or forgets it, and because it is a debt upon one's conscience. Others, including Ibn Taymiyyah, hold that making them up is not legislated, as no new command has been reported regarding it, and by analogy with Hajj and praying before its prescribed time. The preponderant opinion is the first one, which states the obligation of making them up. This is the more cautious approach and clears one's conscience. One must make up what has been missed until a strong presumption of having cleared one's conscience is achieved, according to one's capacity and without causing harm.