Hello,
To explore kvm installs via Virt-Manager, I tried win7 installs in 3 different hosts. All 3 have 2G of RAM or more.
Windows 7 Ultimate in 2.5 GB DVD ISO
1) Centos 5.4, AMD am2, Athlon 64 x2 4600+ works 2nd attempt after setup of Br0 (bridged network) virt-manager-0.6.1-8.el5 kvm-83-105.el5_4.13
2) OpenSuSE 11.2, AMD am2, Athlon 64 x2 5200+ works with defaults (Br0 is setup on OS install) virt-manager 0.8.0-5 kvm-0.11.0-4.5
3) Centos 5.4, Intel LGA 775 C2D, E7600 3.0 Ghz fails in shelled kvm and Virt-Manager with Br0
the Intel C2D box works so well - cooler and faster then the other two - but somehow the kvm intel support seems flawed. The win7 install gets past 2 boots and issues a VM exception in vcpu0 right after the third boot.
Maybe someone else succeeded with a similar Intel setup.
Have you run memtest86+ on the system? Does the motherboard support VM technology and is it enabled? Does the Intel motherboard need a bios update?