I have an oldish Acer Laptop that has been working fine up until today. When I plug it in, it keeps beeping (a constant steady beep) and it's not charging. Is it trying to tell me the cord is dead and I need a new one or is something else wrong?

Sounds like a heart rate monitor like on tv with its beeping

If there is no pattern to the beeps ie. 3 beeps, skipping 1 and then repeat, I'd say it's either the motherboard or the AC adapter.
What's the result if you remove the battery and then attempt powering the laptop on?

You can also try powercycling the motherboard: Remove AC adapter, battery and all peripherals (everything externally connected, like USB etc.), then hold the power button down for ~30 seconds and release it.
When done, connect AC adapter and battery again and see if the problem has changed when you power it on.

It's just constant beeping at a rate of about 100-110 beats per minute. hm I haven't tried removing the battery yet.. I'd have to take the dumb thing apart and unplug it from the motherboard. --- and I forgot to hit send... it's odd the cord works another laptop but not mine anymore... I went to Best Buy and overpaid for a new cord and the new cord works. lol