H4 is still volid after divorce?

[helpeb1]

I and my wife divorced 2 years ago. I have a H1B, she had a H4. We just remarried 0.5 year ago. During this 1.5 years long period, did she still have a valid H4 status? if not, which means she was illegal in this country? If she also submits a application for green card, is there any way to explain what status she was in that 1.5 years period? Thanks in advance. Helpeb1