Phone has been freezing up and now it just says hello on the screen.

This has been happening to the LG Rumor 2 a lot. Even if you took the battery and Micro SD card out then put the battery back in without the Micro SD card and turned it back on, it may still flash Hello. Even rebooting after a few moments with the SD card back in still doesn't help. It's a software problem. You need to take it to wherever you bought it and see if they could reflash the Bios. Don't try talking to customer service at Virgin Mobile, it's a complete waste of time as they will adamantly blame you for it and proceed to give you the runaround. Saying things like they never had this problem before or repeatedly asking if you got it wet and whatnot. Your better off getting another phone, honestly.