Phalaenopsis Roots Almost Gone

[morningleaf]

Hi! I'm new (both to the forum and to orchids!) so I hope this thread is in the right place and everything!

I've recently been put in charge of my grandmother's orchid, and it's not in a very good state. She had it in standard potting soil, and the roots are almost entirely rotted away. There are several short, white, wire-y roots coming from the plant, and a new one just starting to pole out. I was wondering if there is anything I can do to encourage the growth of new roots, and hopefuly save this little orchid! I did repot it in proper orchid mix, but without roots its a tad bit unstable.

Thanks guys!!!