how to fix the disk drive letter is automatically vanished after i reboot my pc

Question

how can i fix that, my disk drive letter is automatically vanished. yesterday i bought a brand new hard drive that have 500gb capacity and i fit that hard drive hdd in my pc by myself . After that i make partition and set disk drive letter name "D" and it works very finely i put my photos, videos, data and many other files or software's . After that my all work is over and i shut down my pc normally. When i woke up from sleep i on my pc some time later i found that my hdd named "HDD (D)" that vanished . I thought that the sata cable must be loose and i checked that all good there. I searched that on youtube, google, chat gpt i found no solution. Then i checked in disk management i looked that my disk is connected but no more disk drive letter so, i put the disk drive letter name "D". then the disk is visible in file explorer then i restart my pc for some reason i looked that the disk again not visible . i repeat the process then it's visible then i restart the pc again it is not visible. so, i do every single steps like drivers update, un-plug the plug it and many more steps to resolve it. so, i request that please anyone know the solution please tell me as soon as possible.