hardwood flooring

Hammer and nails.

Your question is rather broad. What has to be repaired? Do some searching and you may find the information you need as it is too lengthy to reply in a simple newsgroup post. Check AskThis Old House as they did a segment on repairs last year.

frogs, it would be very difficult to patch and match the area with the main floor. What I did on a 80 year old house was left the floor furnace cover screen in place and had the HVAC guy convert the area to a return for the new a/c system. Muff

"Bernie Hunt" wrote on 18 Aug 2007 in group alt.home.repair:

The flooring isn't nailed to the joists -- it's nailed to the subflooring. I'd put down a layer of 3/4" plywood. One inch subflooring is probably only 3/4" in actual measure, and more than 3/4" is needed to anchor the nails properly, not to mention you need to eliminate flex as much as possible.

I agree that it's mostly nailed to the subfloor, but most every reference I've found on the net says to nail into the joints. For example;

Bernie

"Bernie Hunt" wrote on 18 Aug 2007 in group alt.home.repair:

That web site has pretty good instructions. The nails for the floor nailer will be 2" - 3" long, but they go in at a 45° angle, more or less, so the vertical penetration is about half the nail length. Depending on your subfloor, you will probably never touch the joists. On the other hand, having the nails over the joists might make the floor squeak less.

Read the instructions that come with your flooring. They will tell you what type of nails to use and how to space them. You need to do it as instructed to protect your warranty.