If anyone has been having difficulty installing MDT on a Windows 7 machine, I may have a viable solution for you.
I have noticed that after Windows 7 SP1, MDT was unable to be installed on my machine, until now. I did a little research and found a small executable called SafeMSI.
SafeMSI allows you to start the Windows Installer Service in safe mode. While in safe mode I installed MDT without incident on a machine that it would fail to install on.
SafeMSI can be downloaded from Cnet or directly here:
http://www.windowsitpro.com/article/tips/jsi-tip-9233-safemsi-exe-freeware-starts-windows-installer-...
The steps to install are:
1)Download and extract SafeMSI
2)Boot into safe mode
3)Run SafeMSI ; you will receive a message that Windows Installer Service is running
4)Install MDT
5)Reboot