Can't open programs or connect to websites

Okay, basically I'm in trouble...

My girlfriend has a MacBook from about 2007, running OS 10.5, and asked me to see if I could speed it up a bit. I'm somewhat familiar with Macs but have more knowledge on a PC. So I Googled "how to speed up a Mac" and found a site listing a few steps that may help. One of them was to install a sort of file cleanup app, like CleanApp or TidyUp. I ended up installing Yasu, since it got good reviews on Cnet, so I figured it was a solid starting point. Another one of the steps was to go to Library > Preferences > Show info, then check the box for "Locked". So I did. I wasn't able to clean anything using Yasu because I needed her password, so I closed her computer and kind of forgot about it.

This morning she opened her computer after I'd left for work and saw Yasu asking for her password, so she entered it, not realizing what it was. She told me it then ran its cleaning process. When she tried to use Safari, she couldn't get to websites, getting an "unable to establish a secure connection" message. She couldn't use QuickTime, so she uninstalled it then tried to reinstall, which she apparently couldn't do. So she called me told me about her problems. The first thing I thought of was to unlock the preferences. She navigated to the folder and told me that many of her folders had duplicated themselves (ie there was "preferences" and "preferences - original") and also informed me that the box to uncheck "lock" was now greyed out. So it's locked, and staying that way...

What did I do, and more importantly, how can this be fixed? Any help would be appreciated, but being that I'm over an hour away from her and I'd need to explain/instruct her over the phone, the simpler, the better. Although I understand if there is no easy fix. Thanks in advance.

 

I'm on her computer right now and can't seem to do that. I've tried restoring the Library folder from Time Machine but don't have permission to do so (even though she is an administrator) and I'm also unable to copy using terminal, even when I precede the command with "sudo". I tried holding command+R to boot into recovery to do a full restore from backup in recovery mode, but I can't even get into recovery mode that way, it just boots up to the user selection screen. I've been working on it for over two hours, looking all over the internet for solutions. Soooo frustrating...

 

Unfortunately, she doesn't have that either. She's moved a few times since she got the computer and must've lost track of the disk at some point.

 

Ha, maybe... Do you think that'd normalize everything? Would she have the same problems just on a new OS?
Also, when using Time Machine last night, I mentioned my attempt to restore the Library folder, but was met with a message saying "cannot change or delete this folder, as the OS needs it to operate", or words to that effect. Do you think I'd be able to delete the contents of the Library folder (not the actual folder), then restore the old contents of the TM Library folder? I was hesitant to do that last night, as I didn't want to further mess things up...

 

Yikes, those both sound like bad ideas now...