Provider saying there might be a problem

I have a graphic design laptop from my job (it had been used by another employee beforehand), and trying to figure out what may have happened. To note, I'm using a wireless router at home, but have WEP setup on it. I got a warning from my internet provider, and they temporarily locked my account. When I contacted them they had received a letter that I had uploaded a file through EMULE that was copyrighted. The computer does have EMULE on it, but never used to download anything copyrighted. They gave me the name of the file (which when I searched online for what it was, was some game for Wii and Nintendo DS). I searched the entire computer and couldn't find the file.
Could it have been a glitch? It's making me paranoid.

 

It's not hidden either, and the name of the file is mysims_kingdom according to my ISP. My ISP had suggested it might be a problem malware or a hijack, and something about IRC. So I'm not exactly where this should be posted.

 

http://en.wikipedia.org/wiki/MySims_Kingdom
It's a game for the Nintendo DS portable game system.

Emule might have been set to start with Windows by the previous user. When you started the laptop at home and logged into your wireless network, it would have connected to the Emule network and shared that file. Uninstall Emule to insure there are no misunderstandings in the future. Your ISP will take no further action unless they receive another notice.

 

But how could emule have shared it if it's not anywhere on the hard drive? I checked emule, and there wasn't a partial file or anything. I'm just nervous it might be some kind of hack. I ran hijakthis, but didn't notice anything. (Although I'm not that familiar with it, but nothing looked weird).

 

Hi

I'm guessing your wireless security was compromised. WEP is outdated wireless security... today, the standard is WPA (at least), or WPA2. WEP is fairly easily "hacked" into, so the likely story is that someone piggy-backed your internet connection to download the file, hence your ISP's referral to a hijack.

My suggestion: Configure your wireless connection to use WPA2 wireless security with a strong, random password (capital letters, lowercase letters, numbers, etc.). If your router doesn't support WPA2, you can get a router for $50 or less that does (Linksys is popular and user friendly).