think that the Sysinternals Tools have some program to show what programs hold a filehandle to a file,

Yes. it is called handle.exe:

C:\test>handle /?

Handle v3.42
Copyright (C) 1997-2008 Mark Russinovich
Sysinternals - www.sysinternals.com

usage: handle [[-a [-l]] [-u] | [-c <handle> [-y]] | [-s]] [-p <proces
+s>|<pid>] [name]
  -a      Dump all handle information.
  -l      Just show pagefile-backed section handles.
  -c      Closes the specified handle (interpreted as a hexadecimal nu
+mber).
          You must specify the process by its PID.
          WARNING: Closing handles can cause application or system ins
+tability.
  -y      Don't prompt for close handle confirmation.
  -s      Print count of each type of handle open.
  -u      Show the owning user name when searching for handles.
  -p      Dump handles belonging to process (partial name accepted).
  name    Search for handles to objects with <name> (fragment accepted
+).

No arguments will dump all file references.
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