When install the Windows 10 Technical Preview in a Virtual PC or a Oracle Virtual Box, you will get the following error message after the Windows logo
Your PC needs to restart.
Please hold down the power button.
Error Code: 0x0000005c
It seems as if the 32 Bit edition is not as stable as the 64 Bit. I believe Microsoft is trying to migrate away from 32 bit.
Try installing the 64 bit edition on the Virtual Machine. Of course this is on a newer machine so I suspect this might be one reason for the ease of install.