Remotely Setting the Time on a Windows Machine

Use psexec.exe from an admin account on a remote system and send this command below. This can be from a Domain Admin account or if the machine you are logged onto has the same exact Admin account...
psexec \\MachineName w32tm /resync

PsExec v1.98 - Execute processes remotely
Copyright (C) 2001-2010 Mark Russinovich
Sysinternals -

Sending resync command to local computer...
The command completed successfully.
w32tm exited on MachineName with error code 0.

Then check time with...
net time \\MachineName

Note: You can specify a username to execute this command as, but the password will go over the wire in plain text.