I have a custom made desktop that dual boots Windows XP SP3 and Linux Ubuntu 18.04.4 LTS. My Windows XP OS is on a 500gb hard drive and the Linux OS is on a 1TB hard drive. The Linux OS is the primary startup OS. On the Linux Startup page menu I can select the 500gb hard drive with the Windows XP SP3 OS. The problem is when I select the Windows XP SP3 for bootup the systems clock is off by about 4 hours. Do anyone know what is causing this?