Why is my Galaxy S3 stuck on the samsung logo?

Boot into recovery and wipe data or factory reset

Sounds like you reset the phone from the settings menu, correct? Try this:

Hold Volume UP, and the home key down at the same time. Now, while still holding those two keys, press and hold the power key.

When you see the Samsung logo you can let go of the power and continue to hold the other two keys. You will see a screen with blue text that says "Android Recovery" at the top.

Now use the volume down key to scroll down to "Wipe Data" and then use the power key to select it. On the next screen scroll down to Yes then again select it with the power key. This will hard reset your phone.

When it boots up, allow upto 15 minutes for it to fully boot.

Report back with what happens!

If you can't boot into recovery and only download mode and can't recover via Odin your eMMC chip is dead known as sudden death syndrome with the S3, or it just naturally died. Your options here are removing the eMMC chip and using a micro SD as bootable storage (last resort)

try recover via odin etc first

I tried to use your solution, but when I downloaded the odin 3.07 I got a browser hijack spamware and just got done getting rid of it. Now I downloaded Avast to get rid of it it wont let me download it at all due to malware stuff in it. http://spacyroot.com/

You might have to reset the p-ram . In iPhones,this is achieved by disconnecting the battery and then reconnecting it. Hope this helps you out with this problem.