theres a slight problem in that you need to know the old working MAC address if the asumption is right, probably the easyest way, is to look at the routers log and get your old working mac from there, you open a url in any browser for the routers internal webpage, something like
http://192.168.1.1 depending on the make model etc, if you need more help, tell us the router info and we can try and find it for you....
moving on:
the simplest way to change your MAC address if your in windows XP etc is
open start/ control pannel/network connections
right click your ethernet card that "HomePlug" connected to
click properties
click configure
click advanced and look for the "network address" click that and in the "value" section put your old mac addess as one No. like so
if the old one was
00.00.00.00 so put
00000000 in the "value" section
Ok it, and your done, it should now work, if, as above the "HomePlug" used that mac to make the original key....
OR ,for changing the key in the "HomePlug" if you go that way, your going to have to work that out as per the link above ,install the "HomePlug" SW, connect up each unit to the PC, and run the key generating app i assume..., put it all back as it was, and it should be working again ....
"I would use just a long ethernet cable but I am upstairs and at the other end of my house so its not really practical to send a cable all around the house
"
thats seems to me to be a very easy thing to do, far easyer for you than this techy stuff.....
the fact your upstairs should make it easy,
you can have an ethernet run upto 300 feet, so you could simply feed the ethernet through your bedroom ceiling , up into the loft, along the top of the outside brick, drop it down the back of an external drain pipe or somthing, and in through a small drill hole after you put a loop in it below the hole, into the room/wall were the router is, back filling with hot glue or some form of sealent to keep away any little water that may run down the cable/wall/pipe later, all in one long good 'heavy' quality sealed ethernet cable run ,done...
"Another thing I probably should have mentioned before is that my parents computer is the one that has the control of the router I think. Unless I just haven't figured out how to get to the settings on my end . . .
"
looking at your OP pasted chain above, it seems anyone pluged into that router can get to it with the right URL as per
http://192.168.1.1 or whatever it is for the router managment.
so if you dont have the password, ask your dad or whoever set it up originally for the right URL /password to get in and look at the router logs to get your original working MAC
you will know its your old one as you say you havent got in there yet on this new PC ethernet, and you can find out the other PCs with your "ipconfig /all" on each PC to rule that one out in the log, if you see what i mean
these are the things you need to do when your PCs blow up
and you didnt keep a note of these things handy, assuming that old one is on the motherboard and not a simple PCI card you can just pull out and refit inside your new PC OC....