I have an inspiron 620 i am facing problem with upgrading gpu the bios is kinda locked or fixed can somebody unlock it to support every gpu
The Inspiron 620 uses legacy boot for the graphics and does not have a BIOS that supports UEFI booting.
What graphics card did you try to update to?
If the new video card does not support legacy booting (is UEFI only) then it won’t work.
vBIOS on GFX card may need GOP removed 
@M_Bilal As Lost_N_BIOS has said if the new card has a hybrid BIOS with both legacy and UEFI (GOP) it’s possible to remove the GOP section so it can boot in legacy mode if there is some kind of conflict.