Overstay for 6 or 7 years

If she was found out overstaying for such a long time, she will be jailed and fined.

There are three outcomes:
1) administrative detention for 15 days for visa overstaying. She will then be deported and banned from the country for at least a decade.
2) administrative detention for 15 days for visa overstaying plus fine of 20,000 CNY and another 15-day detention for working without a work permit. This is the most likely outcome. She will also be banned for a decade.
3) criminal prosecution (very rare). She will remain in police custody until time of trial (which can be between 6 months and 2 years). Then depending on the outcome she will continue to be jailed until she has served her sentence. She will then be deported and banned for 10 years (although as a felon she will not be able to receive any visas from any country in the future).