It is a file.. What did you do before getting the error? Can you boot into Safe Mode and check in the Event Viewer what exactly happened?
Things to try:
If you suspect some specific device, then check the properties for that device in Device Manager. Driver->Driver Details will tell you what files this device uses.
Find that .sys file in your computer and check its properties - you may see some manufacturer info there.
Find any references to that file in your registry and figure out what device program it belongs to. Uninstall that device in Device Manager.