That hack name doesn't make sense. Fiddler is a debugging program for watching web traffic.
http://www.telerik.com/fiddler Please copy the text and/or paste screen captures here and we can help you with that issue, hopefully. While working as an IT support technician, I had a 95% success rate in removing malware by following various procedures.
When you have to run a chkdsk, this is usually a sign that your computer wasn't turned off properly and Windows didn't close down programs the proper way. In general we try to avoid doing that, however, there are cases when we have no choice but to exit abruptly causing the chkdsk process to kick in. Other times, if you did not invoke a chkdsk (running it from system tools, the command prompt, or reset your system, then this is a sign of hard drive problems that have been detected.
A chkdsk will take your data and hopefully recover the bits and pieces it can find in the Master File Table or MFT, and link the file bits together. If it can't recover the data, it will, as deneban said, put stuff in the root of the C:\drive, or any drive that chkdsk was run on. these have the name file0000.chk, file0001.chk, etc. as they are numbered sequentially. In some cases there are folders that contain data. These are the recovered folders and are named similarly. There is a problem, however, it can be difficult finding which files belong where, especially with Trainz TS12, or any version of Trainz for that matter.
As has been suggested, your best defense against data corruption such as this is to have offline backups whether this is on a thumb drive or an external hard drive. A drive is recommended due to space and speed as thumb drives are slower and usually smaller.
John