Need Some Help!

[Musezik]

I Need Some Help My Peeps. I have this 240sx that has a k24de that is turbo. The person that I bought the car from said he raised the boost up and blew something. I know the head gasket is blown since the oil and the coolat are mixing together. Lots of white smoke comes from the exhaust and the engine. He said he checked the compression and it was low in every cylinder. The guy that I got the car from said its the piston rings. So what I'm asking you guys is how can I check if the piston rings are bad when the head gasket is blown?

Thanks.