It's probably because it syncs the time from the internet and it constantly syncing, behold you can't change the time unless you do something about it.
If you're running from a virtual machine, some programs for virtual machines like VMWare for example will automatically sync the system time to internet time as well or your main host system time, so that could be something as well. But this is only if you're running Windows XP in a virtual machine.
Windows XP is kind of an old operating system, so maybe it doesn't sync with time automatically when daylight saving time ends or begins like newer Windows operating systems do. It has been discontinued also, so maybe you need to set it to standard time from Daylight saving time to regular time.
Go to the date and time settings, anything you may need to change?