A driver is attempting to complete an IRP (I/O Request Packet) that has already been completed.
Suspect antivirus drivers, disk defrag drivers, disk quota drivers, network drivers, any driver that wedges itself into the filesystem or networking stack, and start uninstalling those.
If it was working fine before and isn't now, determine which driver(s) were installed between then and now.
I've searched my resources and there are many many drivers that are known to cause this problem.
I'd start by going to Windows Update and updating drivers there.
-Noggin