Dead or not?

My Ultra+ 256G refused to boot my laptop this morning. The system is hang trying to detect SSD (even CapsLock does not work). When I replaced SSH with HDD - it is all fine, OS is booting. When I put SSD into USB-SATA cradle - it is not recognized by the OS, like if nothing is inserted to USB.

The disk is only 3 months old.

Anything I can do to diagnose or repair? Thanks.

if it is not detected there really is not anything you can do. contact sandisk support to check warranty status.