I have a VGN SZ450N, its been 2ish years since I got this computer. It's been running decently with a few hiccups.

But the main issue at hand right now is the battery.
Background: The original charger is a little frayed so i decided to use an antec generic charger i was using on my asus before the power plug socket broke, and to my surprise the vaio's port started to become loose so i stopped using the antec and kept on using the frayed one. The issue now is in some possitions it stops charging, but if you move it a little it's fine.

The issue that is at hand is that the battery is acting really weird. Some days it will charge to 100% normally no problem, some days it does the reverse it actually decreases the charge to 0% and then shoots up to 100% according to the animation icon. Now however after running it down to nothing it stays there at 0%.

It only works plugged in... any ideas? is it a bad battery? or bad port?