What would make my clock on my task bar, slow.

I have to keep going into settings and updateing clock, its running 10 mins slow

All your other clocks are 10 mins fast

What version of windows are you running?

The reason i ask is that Win 7 connects to the net and checks.
Previous versions would do this too.

So if your pc is not connected to the Internet then its probably showing its age and the answer may just be manage it.

If its a New Pc then that's a puzzle
Try changing the BIOS Battery that could help.

In Windows Help Centre there is a bit of stuff about synchronizing your computer clock which may help.
Right click on the time in your task bar>adjust date/time>internet time>time synchronization.

Bios battery, flat and circular ... Find it on the main board, replace with type cr2032