The Lenovo B575 is a 64 bit machine. I installed Win7 32-bit to run some old programs which we could not get to install on 64-bit Windows, even with its "compatibility solution". (Those same programs run fine on Zorin's Win App Support on other computers.)
I'm trying Zorin on our personal PCs in hope that we will be able to use it (Pro) on our business PCs as well.
Following partitioning directions in another Zorin post, I was able to install Zorin successfully on this laptop (I think) until the very end when GRUB installation failed and it would only boot to: GRUB _
GRUB Rescue did not help.
Since I'm working on a cloned copy of my daughter's original HDD, I can experiment on the copy.
Another reply in this post suggested Super GRUB 2 so I'll explore that and post my results.