Just like troubleshooting any I/O, (in/out), card, be sure the slot the card is in is functioning, you can always switch the card to another slot on the motherboard.  Be sure that the card has been assigned an IRQ by the Bios, preferably IRQ 10 or 11.  Can the card be bad right out of the box?  But, of course.  

A big issue here with any I/O card, but mostly with Network cards is to have the proper driver.  Windows will look at cards and load drivers it believes will work...  that does not mean they will work!  If you did not receive a disk with drivers when you bought the card, then download them from the manufacturer's web site.  If the card is too old to have drivers available or just an odd card with no drivers...  even buying a low-end card is better than fighting this nightmare.

We recently built 20 rackmount servers with two network cards in each computer.  Out of the 40 cards we installed, one was bad right out of the box.  It does happen...  and if the card is bad, it is hard to troubleshoot.  That is why we keep extra cards around, so we can switch out any card that does not seem to function properly.  You can pickup an extra card cheap Network card for under $16 dollars, (in the US), to switch out a card that does not seem to be functioning.  

The best way to insure that the hardware you are using is working is to BE CAREFUL with it during the installation.  Computer components fail most often because of mistreatment...  dropping them, banging them and so forth.  Yes, heat is a killer...  so is static electricity...  but, more components are damaged by mistreatment than anything else.