I wouldn't waste my time with new walwarts and whatnot. Also, never ever charge via your laptop, it's not a good practice as if anything goes wrong (and it sounds like something is wrong) it can fry your laptop, which will then not be covered by any sort of warranty you might have (I'm talking about the laptop).
While it is 100% best to charge externally it does sound possible that your device is faulty, as it is not behaving as it "should" when charging. It's possible that if you inserted a fresh, externally charged battery, the device could work (and assuming an authentic, genuine battery with the right specs for your battery needs-- if you could let us know the make and model and age of your battery, as well as where you bough it, that could also narrow down the problem as if you are using a rewrapped inauthentic cell, it could cause "funkiness" in the mod, etc.,) well, that still leaves the issue of why it
won't charge via USB, as although it's not
recommended to charge via USB, if the manufacturer states it CAN charge via USB, it should function normally.
So, I'd say more info on your batteries would be needed, and if they're not authentic or purchased from a reputable battery supplier, I'd get your hands on some. Start here:
Mooch's blog | E-Cigarette Forum I'd link the table where Mooch lists all his battery ratings and the last cell offers a list of authentic, trusted battery sellers who only sell authentic batteries, but I have not had luck with that. You also need the correctly rated battery for your device and vaping style.
If that doesn't do the trick, I would definitely warranty it, even if you can get it working "sometimes." Given that it's not charging via USB (and it should) once you are sure that your batteries are not at fault, warranty it, even if you can get it to work, charging externally. Electrical "faults" can spread... over time. So, (again, if your battery is okay) but you can't GET the mod to charge via USB and it should, I would most certainly warranty the device. The last thing you need is a slew of increasing, electrical failures that may result in a "catastrophic" failure over time, etc.
Best of luck and I hope you can get it resolved quickly!
Anna