Inspiron 1526 - hardware virtualization

Problem when enable hardware virtualization.

Step-by-step:
1. Enable hardware virtualization in BIOS
2. Install Microsoft Virtual PC 2007
3. Enable hardware-assisted virtualization feature in Virtual PC.
4. When I create and start virtual machine, computer is freeze after few seconds.

When disable hardware laptop work OK, but I need this function for my work...

P.S. I can't write message for support to dell because web-interface (for my Service Tag) does not found any correct available e-mail servers.