A failed installation is never a good thing and yes, I have been in this situation where installing an application has caused my PC not to boot. Not a good feeling.
I have my PC set up with an extra drive (D:) that I place all of my stock media and a daily backup of my C: drive using Acronis TrueImage. It does a full backup once a month and runs every morning at 7:30am to do an incremental backup of any changes from the day before. If a catastrophe strikes, I can boot with the repair CD and restore my computer to the state it was that morning or any day I’d like in about 20 minutes (and I’ve had to do this twice!). Once bitten, twice shy as they say. You may want to consider this a lesson learned and set yourself up like I did. It is set-and-forget easy and, as I said, has saved me several times.
If I were you I would boot with the original Windows XP CD and do a repair install. That is not the same as using the recovery console. What you do is proceed as if you are re-installing Windows and then right after you accept the license agreement Windows recognizes that it’s already installed and asks if you want to repair the install or install fresh. Select repair the install and it will proceed to reinstall Windows over what you have leaving all of your applications in place. I’ve done this several times to recover from the problem you are having (that was before I started my daily backups which are much quicker to recover from)
Here is a web site that describes the process in more detail. It is worth of a bookmark! 😉
How to Perform a Windows XP Repair Install
Good Luck!
~jr
http://www.johnrofrano.com
http://www.vasst.com