I read in a book (whose title escapes me at the moment) that Dell uses Intel motherboards and Intel chipsets... so chances are, the video drivers would have been intel extreme graphics (possibly intel extreme graphics 2, depends on the chipset).

If you had the dell service number (which would have been on the back panel or on the motherboard somewhere) you might have been able to hit dell's support website http://support.dell.com/home.aspx
In the left column there is a panel that says "customize support", click the link "select a system". Then enter the service tag into the text box. Then you can get all of the drivers and manuals for the machine in question.

This can really be helpful if you are like me and frequently buy used computers.