Car wont start help PLEASE.

[Flybiyou]

Ok yesterday the car started up fine in the mourning then after work I put the key in and waited a few seconds and turn the key lost all power right before this the TT was reading 12.3 volts slowly the lights in the car and dash TT and AFC came back on took the key out and tried it again same thing battery voltage is reading fine jump start it and it starts. Well this mourning I go to start it again and same thing happen it will jump and run but you take the key out and try and start it it wont it loses all power and the dash lights and assesorys come on slowly this mourning my TT back light stayed on but with nothing showing I dont get it any ideas at what I should do. Im going to get a battery right now but it shouldnt read 12.3 volts and not crank all lights in the car were bright right befor I turned the key. This is my daily so I have to get this thing going today any ideas or help from you guys would be great.
Thanks
AJ

 

[huafist]

Try cleaning the contacts from your battery to your cables. If that doesn't work, it's time for a new battery.

 

[leet]

Moved to Problem Diagnosis Forum.