Dell Inspiron 3800 help!

[aaron_toler]

For some reason (I know its an old model but its been doing fine) wont start up right. When I start the computer it starts up just like it normally does and says the battery is low. I have it hooked up on wall power but after a few seconds it will shut off. I dont touch it and it will come back on if its still hooked up to the wall. I bought a new one today but I was gonna give this one to my mom for her just to surf the internet. Is there a way to fix this problem?

 

[mcojettech]

Might need a new cmos battery