Help, please ! I've done something silly !!

I googled into your site looking for basic tools to explore my home network.

There's a Netgear 'SuperHub' = cable-modem / wireless-n AP / router, a Sitecom hub, a pair of cabled PCs, a pair of NAS drives and an all-in-one printer, plus a 20 metre cable to a *second* hub feeding BluRay box and 3 metre cable to a Sitecom 300-n range extender configured as WAP. There's also a floating population of lap-tops hooking onto the WPA2 WiFi...

I downloaded several of your network utilities, found one had defaults which flew through the network and found everything on-line, complete with their x.x.x.x addresses

Then, while playing with the advanced options, I did something which caused the utility to find nothing thereafter.
ops:
I un-installed & re-installed repeatedly, but it was as if my network did not exist...

So, my embarrassed questions are (1) Which utility was I using originally, and (2) How do I reset working defaults ??