The CMOS battery is not the cause, if the time loss is while Windows is running. The battery only holds the settings while the computer is switched off.
Have a look at these possible causes:
Windows Clock on Taskbar and in Date/Time Tool Loses Time
http://support.microsoft.com?kbid=189706
The System Clock Slows If You Run a Program That Uses Sound Extensively
http://support.microsoft.com/?kbid09296
Restart or Network Connection Changes Computer Date and Time
http://support.microsoft.com/?kbid3912
"System clock loses time when using Norton AntiVirus 2000"
http://service1.symantec.com/SUPPORT/nav.nsf/df0a595864594c86852567ac0063608c/04
73528ab04a4365882567fd00760e7c

Signature
Glen Ventura, MS MVP W95/98 Systems
http://dts-l.org/goodpost.htm
> Im having a problem with the mouse not responding at times
> and the clock is a few hours slow. I changed the battery
> and on the motherboard and still seems the same???