How do I trace the origin of a DNS resolution in Windows 7?

Hosts involved:

* Windows 7 host `WIN7` where I'm trying to remove the name-to-IP mapping
* home router running a DHCP service
* host `ABC` renamed to `DEF`

On a Windows 7 host, I had a name `ABC` mapped to an IP number via `C:\Windows\System32\drivers\etc\hosts`. I removed the mapping from the HOSTS file. I renamed the Linux computer `ABC` to `DEF` and had it re-register with the DHCP server running on the router station (a Synology product) using its new name. (Just in case the DHCP server on the router would use DHCP leases to also offer some name resolution services.)

I issued a `ipconfig /flushdns` on the Windows 7 host from an elevated command prompt. I even stopped the DNS cache using `net stop dnscache`.

[Update:] An `nslookup abc` returns `Non-existent domain.` The host DNS queries are relayed to is the router I mentioned above. [/Update]

And yet, a `ping abc` still resolves the bloody name to the wrong IP number, to the one I had removed the mapping for. What can I do to trace this issue to its root?

[Update 2:] I rebooted: the issue persists. I unplugged the Win7 host from the network. (Well, switched off WLAN.) The system still resolved `abc` to IP number `192.168.33.102`, directly subsequent to an `ipconfig /flushdns` executed as `Administrator`. Which leads me to conclude that there is some local system cache that remains unaffected by `ipconfig /flushdns`. [/Update 2]

A related question (but confined to the cache flush issue, and just flushing doesn't solve the problem for me): [How do I update / flush / reset my DNS records in Windows?](https://superuser.com/q/317385/69392)