I have the Samsung droid Charge (SCH-I510) and I tried to load bootloader to it and now the screen is just black.when I insert usb to it,the buttons at the bottom light up but the screen is just blank.I there anyway to connect the phone to a pc so I can flash it I don't care about the files on it.
You have to use ODIN to reflash your phone. Its the last resort I can say for your phone. I was too in same situation. I was having Sammy's Galaxy S which on rooting and upgrading went blank. I used ODIN and refalsh it with stock rom and made my phone alive. Give it a try. See the link here it might help. There might be some problem with your network after recovering. See Link. Its for Verizon. Kindly find your appropriate ROM and flash it. XDA forum is great resource for Andy users/developers
The only way that I personally know is to flash a custom recovery, and wipe your phone from there. If you can, follow this tutorial to install a custom recovery. Also, the tutorial doesn't mention it, but if you don't have windows, and have macOS or Linux, use JOdin. If you're using JOdin for macOS, install this driver before installing JOdin. If you need any help, feel free to comment on my answer, and I can help you 😁.