1. Packard bells don't tend to be very upgradable.
2. "im lookinjg to do is either buy a cheap PC base unit with a reasonable motherboard and processor and upgrade all of the components ie; the graphics, multiple hard drives, dvd-rw drives"
Doesn't make sense you are basically building a new machine from scratch.
3. Unless you are very specific about what you need then it is much cheper nowadys to buy a unit then actualy build your own plus you get a guarentee and software with a new unit.