said by Bob4:We have other rooms where the carpeting has been removed. The holes don't bother me. I wouldn't say the floor is ruined.
The only way to fix the holes is wood filler then stain it slightly darker so they blend in. No amount of sanding will go that deep. I'll take pictures and post them tomorrow.
There could also be deep stains you can't sand out like pet urine or a spill. Again you need to stain darker to hide that stuff.