I plan to remove a 4'x4' section of 1.75" x .75" inch hardwood flooring
from a corner of a bedroom in order to make a bathroom larger. I was
planning on just using my circular saw set at .75 inch depth and
replacing the blade when I hit a nail.

I've never hit a nail with a circular saw before, and I'm not sure if
this will ruin my $30 walmart saw. Is there a better tool to do this
job with? I don't want to cut the subfloor or I'd just use a sawzall.