HughMartin,
Mobo Batteries are not soldered to the motherboard. Here is a picture of my Mobo:
You will notice the battery above PCI Slot #3.
Binoculars,
You can log on to the Internet if you like, I was just mentioning staying off the Net if you are afraid of logging on without your Antivirus Software installed. Since you leave your comp on 24/7 (as I do), the battery is not the problem. The battery only comes into play when you turn your computer off and removed the Power Cord from the Power Supply.
When you connect to the Internet, do you use a WinModem? (That can cause the clock to lose time too, since it pulls cycles from the CPU in order to run the Modem.)
Take Care,
Richard