Question : Problem: Will my motherboard be compatible with SATA2?

I'm looking to increase the size of my second hard drive to roughly 1Tb, many of the 1Tb drives are SATA2 - is the motherboard in my Dell Dimension 5100 compatible?

Finally, if i were to upgrade the motherboard and processor does anyone have any recomendations?

Answer : Problem: Will my motherboard be compatible with SATA2?

SATA2 is backwards compatible with SATA1.  So yes the drive will work with your system.