Black screen of death?

[olgreg20]

So earlier in the week i flashed my diamond to calkulins v3 rom. everything is running smooth, no problems at all. Then all of a sudden the phone would "freeze" so then id hit the reset button and it be fine, then just last night the phone once again froze and when i hit the reset button the phone got stuck in the black screen after the ("htc touch diamond" screen.) so i did a hard reset, and the phone cant go past the black screen of death. so all i see is a black screen, the phone cant be hooked up to my computer, i cant even charge it. so i called sprint and they told me i can get the next phone up, but i have to go into a tech center and get it looked at first, so my question is, can they find out that i was runing a custom rom and had the phone unlocked? i would like to assume not cause i cant even hook it up to my computer so i don't see how they could. but i don't like to assume. so if anybody knows please let me know.
thanks.