Change date of system at Install

I have the need to change the date and year on the pc during install. I can capture the current date and time.

How do I reset the pc's date and time to a diff value during install then chane it to back to the correct values?

Is there a function to do this?
Is there a function to poll a time server to set the
correct time and date?

You can call SetSystemTime using the System.dll plug-in to set the date and time.