I have a Dell XPS 410 that has been upgraded to a Core 2 Quad processor. Recently I have noticed that I am using about 3.5GB of memory for just surfing the web with Firefox. (IE and Chrome use about 1GB less). Are there 2GB ram strips that I could use on this MB, or would I have to replace it, and if I did, would there be something suitable that would fit?
No. Based on the specifications page for your system, it has a maximum RAM limit of 4GB (4x1GB RAM Modules). In order to utilize more than 4GB of RAM, you'd need to replace the motherboard with something compatible AND purchase and install a 64-Bit operating system.