How do I install turnkey virtual apps on a Microsoft Virtual PC?
Is the Virtual PC running Windows XP Mode or Linux? If it is Linux, Hovsep A has already pointed you towards the correct discussion.
Then, I guess the next logical question would be "How, then, would I do it, wherein, the Vpc is running in Windows XP mode?".
For OP, this is irrelevant since Home Premium does not support XP Mode.
For those running Pro, Enterprise, or Ultimate, it doesn't really matter either since XP Mode is simply a pre-built VM. The Turnkey system is just another pre-built VM that has been packaged to run under VPC.
Turnkey Core in Windows 7 VPC