Strange installation & partitioning issue

Hi all!

I have encountered a strange installation issue here, that's preventing me form upgrading from XP.

I have 2 systems, I is Intel based, the other IS AMD-based.

1: Core 2 Duo, 2 GB DDR2 RAM, 1.5 TB HDD in 2 partitions (OS & Data),
- 8+4 GB Linux install
- 50 GB XP home install
- 50 GB win 7 install

2. (used solely as a PVR) 4 GB DDR3, 1.5 TB HDD, 3 partitions, OS Data, utility/driver/app install backups
- XP MCE2005

I know from running/testing Win7 Beta, & RC1 that the minimum partition size needed to install is about 50 GB, and having run a test install of the RTM/final version, a 'virgin install' is abt 15 gb.

This is the issue: I can install Win7 on the Intel system, designating a 50 GB partition for it to 'live in' just fine, When I do the same on the new AMD system it seems to be acting strange.

1) known good hard drive, no partitions:
initial install, installer gives an error stating 1300 GB required to install (???)) (Ignored as spurious error/glitch)
a) Create 50 GB partition during install process, not pre-partitioned

b) proceed with install, allowing 200MB partition to be created.
installer gets to 'copying installation files' @ 21%, then stops (left overnight)

c) delete all partitions during install, and create a 100 GB partition and repeat ...
installer gets to 'copying installation files' @ 26%, then stops.

d) reluctantly repeat, designating entire HDD for install.
install completed successfully.

This system is only being used as a DVR, so I attempt to shrink the OS partition to <100 GB, Computer Management tool will not allow it to be shrunk to < 750 GB.

The total installation consumes about 15-20 GB of disk space.

I am back to XP MCE, but tired of it's finicky nature.

Does anyone have any ideas as to what's happening here?