You should not have any problems adding a PCI card to the computer.  Shorting pins on the motherboard is not required and would void the warranty (even if it did help get the card to work). In my experience the best way to install new hardware in Windows is to install the drivers and then connect the hardware.  I have had to do this in the past with Linksys PCMCIA network cards, so I wouldn't be surprised if it is still the most reliable way to add a new card to your computer. The steps I would personally recommend are:  
I have a Linksys 10/100/1000 Gigabit NIC (m/n EG1032), which I've tried installing in my Dimension 1100/B110 without success.  I followed the installation instructions from Linksys (i.e., open case and add card to motherboard, then start PC, at which point WINXP Pro should identify the new hardware and I would then select the driver from the disk.  However, the "Found New Hardware" never came up.  The Dimension 1100/B110 comes with an Intel Pro 100 NIC onboard.  I next tried to disable the onboard NIC through the Hardware Manager, and use the Add Hardware feature in the Control Panel, but it didn't find the new NIC on the first go round.  So, I installed the driver utilizing the "Have Disk" option.  The Linksys NIC was installed, but stated that it might not work properly, and a look at the Hardware Manager confirmed that there was a problem (a yellow exclaimation point next the the new device and a Code/Error 10 in the Details section).    The yellow light on the new NIC did flash when the ethernet cable was plugged in, but it didn't connect to the network.  The Windows Troubleshooter recommended removing and restarting the PC, but the new NIC still was not found when Windows booted up.  I next restarted the PC, went into the Bios and disabled the network interface.  The PC took forever to restart into Windows, and still the new hardware was not recognized.   I'm wondering whether there is a pin on the motherboard that I need to short, in order to be able to install a new NIC, or if there's some changes I need to make in the Windows software someplace.  I've restored the Bios setting and have enabled the onboard NIC in the interim, so as to be able to access the internet and my network printer.  Any assistance would be greatly appreciated.Thankx,Jack
Need Help Upgrading to Gigabit NIC in Dimension 1100/B110.