OldGimmer wrote:
Initially I thought that I had somehow dislodged the network card, but I have checked this, including removing it and re-seating but the fault still occurs. Why?
Hi
You know, even LAN cards die one day

It may be a surge problem (when the PSU died) that killed the LAN card or maybe heat or old age or...
It may be that your NASLITE instal has gone bad when the PSU died.
Try with any other "boot from CD" Linux distro. If it sees the lan card, then something weird happened to you NASlite install. Try reinstalling NASlite. If the Linux distro cannot see the LAN card, then buy a new one

Regards
Robby