Help Me - I broke my cart

I'm a total moron here, I don't know how I managed to screw this up as badly as I have but here's my set of issues:

Had a custom site all set up - just a few minor tweaks to make things work correctly. somehow, and I really don't know how, my htaccess files got corrupted, I made some php changes, but they somehow managed to crash the entire way the site works and I can no longer access either my admin section or add any of my items to cart. The url that is now generated when you click on the links is the long url string that is clearly no longer truncated and it's just a mess!!

So here's my question, is there anyway to figure out what the heck I did and fix it? or should I bite the bullet and uninstall/reinstall zen cart and start fresh. I'm really at my whits end with this site and all of the very strange anomalies that have occurred in the building of this cart.

Please help - i really need it:shocking:

try to look up in your ftp client
the files that were recently changed, you can see the date and time
make a list of all the files.

this will give you some place to start
g'luck