Hi

My computer clock loses approx 15 minutes or so per day with a newly installed battery.
Was worse before I changed the battery.

Any ideas ?

Sometimes BIOS updates will help. If your system is under heavy load or BIOS power management is enabled, time can slip. For Windows, boot the computer into safe mode via F8, let it sit, and see if the time still slips. You can also install atomic clock synchronization software to keep the clock accurate. Lastly, some real time clock modules have their own internal battery (nonreplaceable) and the one you can change is only for CMOS backup.

In case it comes down to a hardware issue, as mentioned you can use a utility to synchronize your clock

Here is a freeware utility and you can set it to check internet for correct time and make adjustments as needed

Atomic Clock Sync 3.0
Atomic Clock Sync Information from worldtimeserver.com

Thanks guys...