Your Device Manager will tell you what drivers you need. Go to Start and type in "devmgmt.msc" (without the quotes) and press Enter. Anything with a red X or yellow ! will need drivers. If you can't figure out what the device is, right click on it and select "Properties". Then select the Details tab, then select Hardware ID in the dropdown box.
Most of the hardware ID's will have a VEN_ and a DEV_ in the dropdown box entry. Make a note of the 4 characters after each of the (4 characters after the VEN_ and 4 characters after the DEV_
Then go to
http://www.pcidatabase.com and enter the VEN_ characters in the Vendor Search and search for that. Click on the Vendor link, then search for the DEV_ characters. That'll tell you what the device is.
Verify that your Vista is 32 bit by going to the System applet in Control Panel (Classic View). About 1/2 way down the page it'll say either 32 bit or 64 bit.
What make and model is your system (or the make and model of the motherboard if it's a custom build)? That'll help us to locate the drivers.