Incorrect imac clock

My vintage imac (circa 2007) is having a tough time keeping time. I have reset it about 4 times in the last 2 weeks. Reading around the web I'm seeing that my battery may need replacing. I remember this happening years ago when my mac came in a beige box and ran with a powerPC chip. At that time I replaced a battery that I bought from one of the big mac suppliers of the day. Any ideas?
Thanks, Harv

A 2007 iMac will have a button style battery on its motherboard somewhere. These are not great fun to replace, you need to remove the front case in order to get at it. I think the battery is a CR2032 so they are easy and cheap to buy.

Find your model on ifixit.com and check the guide for replacing the PRAM battery, see if you fancy it.