I realize you're not a programmer (
), but take a second and download the new firmware from your My T-Mobile login and upgrade to the latest; it's better to do this now before you've spent bunches of time with the device and don't have a lot of config time invested. It will most likely fix whatever is triggering your random boot-up error.
I got mine a week or two ago and the "in the box" firmware had bugs that I found right away (changing the left smart key assignment didn't stick, for example - always reset to voice dialing). I went through the upgrade - taking care to NOT save any preinstalled apps or user-data (i.e., I let the upgrade wipe the device 100%) and I haven't had nary a problem since.