That's a socket 478 machine. Probably 32 bit Pentium 4 CPUs. Since then there have been LGA775 P4/D 64 bit CPUs, LGA775 65nm Core2 Duo, Core2Quad, Core2Extreme, then 45nm Core2 Duo/Quad/Extreme CPUs. The fastest P4/Pd CPU just equals the slowest 65nm Core2 Duo. The best 45nm Core2Quads, Extremes and a few Xeons are just hanging in there as low end gaming CPUs. There have been several generations of i3.i5,i7 to choose from since then. It's just too old to bother with. Dells front I/O is proprietary, so are the PSU connectors back then. The case would be the only thing you might use, and that would be a PITA anyway. I like to mod old Dells so this isn't an anti Dell position, it's just reality.