I was intending to delete a file using Shift + Del. I did that, but I discovered that the file is still there, and I deleted another one, but I don't know which file is gone. Is there a log or something to track files operations?
You should install (but not on the same drive as the file deleted from) a recovery utility like Recuva to scan the volume for deleted files.
If you have Windows backup enabled, Windows 7 has a feature that lets you restore a directory to a previous version. You can right click on the direct and click "Restore to previous version" and it will let you revert it. You can copy the contents of your current folder to a temp directory to avoid losing recent progress.