Wood Floor Woes

When I renovated this house ten years ago I was very happy to see that under the layers of linoleum and wall to wall carpets we had hard wood floors.

However, they were never perfect.  The wood was placed with quite wide spaces between the boards, and it had some damage.

Three years with sloppy tenants, and their huge monster dog, and the floors that were passable then are not passable anymore.  I have written about these tenants before and they really destroyed my house.  (Beware of who you let live in your home, because they may not treat it as well as you would like.)

Here is how my floors look now:

The floors here got really chewed up.
I think a lot of wet dog water got down here.

This hole is so big I can't get it cleaned.

This hole was filled in, but now all that wood filler
has been chipped out.

Again another hole that is impossible to clean.

This next shot is pretty bad, so please don't judge.

It is really hard to clean under this.
The radiator leaked and caused a lot of damage.

So the question became: "what to do?"  Jeff and I debated for a while.  We love the wood, but not the shape it is in is so bad that we can't just sand them.

So you get an idea, all of the above problems are in the dining room only.  Here are just a couple of them look from the kitchen.

Do you see the four holes?

At first we decided to use "click and lock" wood.  It is not hard wood, but it can be installed "floating" meaning it will not damage the wood underneath.  We also talked about repairing the floor we have, but that will be expensive.

At the hardware store we decided maybe we should just go for the real hardwood.  It is better, it does not scratch as well (depending on the wood), and it will improve the value of the house.  My only reservations about the hardwood will be messing up the existing floor.  The other problem is that it is much harder to install and we have to nail into the wood floor that is already there.  A friend said we should take out the floor and then put in a new one.  We can't afford to do that.

In the end I'm not really sure what to do.  If any of you have any ideas please let me know.  I need some help.

**** UPDATE: Several people have suggested I replace the bad pieces of wood and keep the original floor.  I appreciate everyone tips, (and I did ask for it) but now I know that the pine floors are just too soft to be good for our family.  Many stores don't even sell pine anymore.  So Jeff and I have decided to get new floors, but don't worry, they will be real wood.****