How do I instal OS X when boot combos don't work? I'm trying to instal OS X on a 2013 Macbook Air. I erased the OS X partition, the computer is booting to my windows 7 bootcamp partition by default. All boot key combinations(C, Option, CMD+Option+R, etc.) are not working, probably due to water damage. I can no longer get into recovery mode, but the files to boot into it are there.

If anyone can help me get into recovery mode I can use a time machine backup to instal OS X from there. Is it possible to change the boot drive from Windows 7? Could I some how delete Windows 7 so that the boot order will move on to recovery mode? Is there a way to install OS X from inside Windows 7?
A long shot, but there should be a taskbar item that bootcamp installed on your Windows OS. If it's still there, you might be able to right click on it and get into options to change boot preference. From what I recall that does not show the recovery partition. I don't have a windows partition at this time so I can't help much there.

another thought I have is you might be able to install a third party bootloader like rEFIt or rEFind and get in from there with a tweak to the config file to choose the rescue partition on startup. 

Does your 2013 macbook have a cd drive? If not can it boot from USB or external cd drive?

It should be possible to tell the bootloader which MBR to boot into before restarting. I think you can accomplish what you need to from a live cd or similar. Doing it from within windows would be difficult but not impossible. There are tools like Paragon's HFS+ that will let you access mac filesystem (system requirements says it supports Windows 7). But yeah, dealing with HFS+ from windows or linux is a nightmare. I think generally the first step is to disable journaling, but you don't have that luxury now.

Apple stores can now reformat apple computers over the network using proprietary tools not publicly available. If they can do that for your 2013 model, it might save you some grief. Although I imagine they would wipe your windows partition so you'd need to back that up before doing that.