Bios reset after battery change

[sophie2]

Hello,
I have a dell dimension 8400 (very old) worked great, then after some time not used I got a 'system battery voltage low' I changed the battery now it won't reboot. I get for long beeps short pause 2 more long beeps. I tried repeatedly hitting f2 to get to set-up to reset bios but it won't go into set-up

 

[treefrog07]

Did you install the battery with the proper polarity? Usually the + side faces away from the board.