Vista 64 will not install

I have a shuttle XPC SN68SG2 NVIDIA GFORCE 7025 chip set
2gb RAM
AMD 64x2 5200+
NVIDIA GFORCE 7300 pcie 256mb video
My system currently runs XP media centre on the first partition of a
dual partitioned SATA II drive.
I am trying to install Vista Ultimatex64 OEM on the second partition,
booting from Vista DVD.
The installation will not complete the pc shuts down during
installation, after restarting I get a startup options screen saying
that windows had shut down - giving me normal & safe mode options.
When I continue in normal mode I get an error message stating that the
computer shut down during installation and installation must be
restarted.

Any suggestions?

Thank you


--
NeilDW