Windows 7 time issues

Solution 1:

By default, Windows assumes your hardware clock is set to your local time, while Ubuntu assumes your hardware clock is set to Coordinated Universal Time (UTC).

You can either configure Windows to use UTC, or configure Ubuntu to use your local time, as Ubuntu's documentation explains:

Make Windows use UTC

Note: This method was not initially supported on Windows Vista and Server 2008, but came back with Vista SP2, Windows 7 and Server 2008 R2.

To make MS Windows calculate the time from the hardware clock as UTC. Create a file named WindowsTimeFixUTC.reg with the following contents and then double click on it to merge the contents with the registry:
Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\TimeZoneInformation]
     "RealTimeIsUniversal"=dword:00000001
Make Linux use 'Local' time

To tell your Ubuntu system that the hardware clock is set to 'local' time:

edit /etc/default/rcS

add or change the following section
# Set UTC=yes if your hardware clock is set to UTC (GMT)
UTC=no