The chipset and type CPU is the key to speeding up your system. Along with a 200 MHz Frontside Bus (FSB) and some PC DDR 2700 (512 MB), a decent AGP 4x Graphic card, and a properly partitioned 7200 rpm Western Digital 8 Mb cache HDD, and maybe a 450 watt PSU. Add a tweak here and a tweak there and burst out of the starting blocks.
I know you don't have this type of system, but the point I'm trying to get arcoss is compatability. The system must have a proper balance of power to get optimal read/write processing speed.
Simply getting a bigger faster rpm HDD will only help a little, unless you have the rest of the system working together in precision. The question is how much are you willing to spend?
Regarding imaging the data on your old HDD to transfer to the new HDD is a snap. You can use Norton Ghost or Partition Magic Drive Copy to do that. Here is some reading that may help: <A HREF="http://www.pcguide.com/opt/index.htm" target="_new">PC Guide</A> Good luck.
<font color=purple><b>An average human brain weights aprox. 3lbs., but a thought weights a load.</font color=purple></b>