It's usually a nickel sized battery on the motherboard. The most common # is 2032. Do make sure you're PC is set to synchronize with some internet clock and that your region and time zone settings are correct. If not, a common issue is that your clock will sync to the wrong zone, the hour will be wrong but the minutes will be OK.
a computer. I know this is the wrong forum for that question, but I knew once, but have forgotten what it means.
Rob

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