I have a Toshiba computer. My time is always 1 hour behind even after I reset it, days later it switches back.

Look for a time zone setting too.

Hi, what your are experiencing I nothing related to your system settigns, you said that ays later it will switch back an hour late this is because the CMOS battery on the motheboard of your laptop needs to be replaced, this will correct your concern with your time. :)

Set your Region and Time zone correctly.
The main cause of this is the Internet Time setting. It synchronizes online and changes your clock according to the Regional settings...

Also check Daylight Savings Time?