Scratch my previous answer. Seems I misunderstood what a "factory cable" is for. It can't actually charge your battery, instead it is used to power the phone so that you can flash/diagnose it, even when your battery is dead. Normally, you need a working phone to charge the battery (with the stock "charging cable").
This information may or may not help you. At the very least, using a "factory cable" may allow you to power your phone on, which would tell you whether the problem is your battery or the phone.
or is this like a chicken and egg problem i now have? a catch 22? i can't charge the battery without a working phone, and i can't have a working phone without a charged battery? golly gee, anybody out there with an MB886 want to charge my battery for me? can i just hotwire the battery to a couple of leads from a charger and bypass using the phone as the charging device? at least to give the battery say 15%-20% to get something to happen... like get this rain cloud perpetually parked above me to blow over from above my head for a day or two maybe?
so, with phone plugged in with "factory cable" here's what i get and when... the phone bootloops on the "bootloader unlocked" warning screen if i don't press anything. volume down gets me fastboot, volume up gets me recovery. phone shows up in both and takes commands... so is it possible i just need to restore a nandroid backup, or is the battery charge the better bet now? i would just try the nandroid for $h!ts and giggles, but the last one i have isn't as fresh as i'd like, but is certainly usable if i must.