I just got my sd card today with noobs preinstalled, whacked it into the raspberry 3 B+, powered it up, green light flashed and went for about 30 seconds now nothing but red light and the raspberry app can’t connect to it. I thought it may have been the old SD card I was trying to use but now I’m guessing the raspberry is dead? Thanks for any info
With any boot problems with the raspberry pi this sticky forum thread on the Rpi foundation site is the best place to get the information you need to get back on track.
If you try all of this and you are still having no luck send an email to firstname.lastname@example.org (assuming you got the 3B+ from us)