For an article I'm writing on C# 4.0, I really need the Visual Studio 2010 CTP (September release). However, as you may have experienced today, January 1st, the CTP is expiring: Visual Studio 2010's "trial period" has expired. The CTP is only available as a Virtual PC image, and a VPC image by default will take the date settings from the host OS.
Now, I found there's a settings in the *.vmc (Virtual Machine configuration) file that disables the synchronization between the host and the guest OS. By activating this setting, the VPC's time will only advance when it's powered on. When extracting the VPC the first time, the time is set to October 10th 2008, giving you all the time you need to play with the VPC.
Here's how to apply the setting. Open the *.vmc file and look for the <mouse> tag.
<mouse>
<allow type="boolean">true</allow>
</mouse>
<video>
<user_selected>
.....
Between the </mouse> and <user_selected>, add the following tag:
<components>
<host_time_sync>
<enabled type="boolean">false</enabled>
</host_time_sync>
</components>
Now, boot the VPC and it will now stop syncing the two clocks.