Re-setting Clock

I just completed all of the steps for Read Me and Run Me First yesterday to remove malware. One of the fixes put my clock to 24hour instead of the way it always has been. How do I re-set it back? I've already been into the control panel and looked it up on Windows help but it says to check my internet connection, well I know I'm connected!
Any ideas? When I try to "Update Now" it says error...the RPC Server is not available.(?)
I have Windows XP Pro.

 

Try this one type ntp.cs.mu.oz.au and click update now.

For the change clock goto control panel then regional and language options then
costomize then time.

 

Thank you! Going to the control panel to Regional and Language options did it.Visiting your site and going thru all of this has already taught me alot.
You guys are super. :cool