10/100/1000 Mbps Gigabit Network RJ45 LAN PCI Card

I bought the above network card from ebay http://tinyurl.com/mt7hmr so that
I could try wake-on-LAN with an older PC that I have in another room.
However, though the card snaps nicely into the PCI slot it's shorter than
the other PCI cards I have fitted to the main board (MSI K7T Turbo) and it
doesn't work. The seller assured me that though it's shorter than I might
expect it should still work, and so he posted me another one, thinking the
first one was faulty. That one didn't work either. I've always thought that
PCI cards were the same length, and if you go to the link I've posted
you'll see that it has two slots in it, which also surprises me because the
other cards I have only have one slot. The question I would like to ask is,
are PCI cards always the same length with just the one slot, or is the one
I've bought supposed to fit a different more modern main board that has a
different length PCI slot? When it's fitted, it's about a quarter of an
inch too short and makes the PC hang on startup.

 

No, the cards can vary in size and NIC's are quite small.

 

The pinouts are described here:-
http://www.interfacebus.com/Design_PCI_Pinout.html
and I suspect you have slots at positions 12,13 and 50,51.

also at:-
http://www.interfacebus.com/Design_Connector_PCI.html
Scroll down to:-
PCI Bus Connector Manufacturers
shows the dimension of the socket and the meaning of the 1 or two keyways.
I am not clear which board dimension you mean when you say "shorter" - as
opposed to "taller"? Height does not matter.
The picture on the ebay link looks like a normal sized pcb to me - I have a
similar-looking D-Link network card in front of me now.

 

The card has two slots as it is designed as a Universal 3.3V & 5V card
to fit either 5V or 3.3V PCI slots. Your K7T motherboard features 5V slots.

Have a look here for details of the keying.
http://en.wikipedia.org/wiki/File:PCI_Keying.png

Why it does not work is some other issue, I'm afraid. I take it by
shorter you are refering to the vertical height, an attribute which has
no relevence to this issue.

Try a linux live CD as a test to see if it can actually be found, and is
just hiding from Windows to annoy ye.