Installation of PCI card causing memory problems?

  My Dimension 8100 has been running very well since purchase.  I have inserted various cards into the PCI slots (e.g. an ISDN card) during the time I have had the computer without problems.

My problems began when trying to install a Belkin USB 2.0 and Firewire PCI card.  During the installation, an error message appeared something to the effect that there was a problem with the PCI Universal Bus and where could the driver (I think this is what the message requested) for this be found.  I was not sure what to do, so I hit the "continue anyway" response.

From this point on, the PC has behaved very oddly, as if it has no or little memory.  From boot-up, the usual programs loaded at start-up (indicated by the icons at bottom right of the screen) will not load properly.  Instead, as each one tries to load, I get a warning box for each stating that there is not enough free memory to run the program, so I should quit the program and try again.  So nothing loads and nothing will run.  I also get a message headed "Service" stating that Windows cannot connect to the E-Support button hardware; at the end of this message it states: "Detail: Bad Namespace".

If I try to open the Control Panel, I get a message stating:  "Windows cannot access the specified device, path or file. You may not have the appropriate permissions to access the item."  Meanwhile, everything operates at a very slow pace, and the PC often freezes, forcing me to press ALT+CTRL+DEL to try to clear things.  Eventually, all freezes and I have to press the "on" button to force the PC to shut down.

I am sending this message from another PC as my Dell is currently effectively non-functional.  Can anyone offer advice about how to fix this state of affairs?

Many thanks.