Hello everyone,
I ran into this fix today when I was trying set the correct time on one of the computers at a computer learning center I work at. If syncing with an internet time server doesn't work, try this (I've only tested it on Windows XP):

1) Click: Start / Click: Run / Type: CMD
2) Type: Net stop w32time
3) Type: w32tm /unregister
4) Type: w32tm /unregister (intentional duplication)
5) Type: w32tm /register
6) Type: Net start w32time
7) Type: exit

Now that you have restarted your windows time service, you can now update the System Time to sync with an internet time server:

1) Click: Start / Click: Control Panel / Click: Date and Time
2) Click: Internet Time Zone tab
3) Make sure Automatically synchronize with an Internet time server is check
4) Click: Update Now

Hopefully that solves any problems you have with syncing your time.

Edit: Also tested on the 32-bit version of Vista.