I have the following graphic card and it allows connecting up to two displays:

Name NVIDIA GeForce 6200
Adapter Type GeForce 6200, NVIDIA compatible
Adapter Description NVIDIA GeForce 6200
Adapter RAM 256.00 MB (268,435,456 bytes)

The displays may function in different ways, configurable. I prefer the one that allows me to work separately on each display but also to pick and drag an open window on one display to the other display. It is most useful when working on a program on one and having the HELP instructions open on the other, just as one example. I have no problem in opening multiple windows with FireFox or Internet Explorer by repeat clicking on their desktop icon. Another issue may be in the browser setting of how it treats new links or pop-ups. It can open these in new tabs or new windows. If Tabs is not a feature in your browser then upgrade quickly. Working with tabs is sometimes preferable to working with multiple windows. You can jump from one to another and back.by clicking on the right tab.