vincescerri:
it always shows error on entry of new sketches or trying to alter a sketch
By "it" do you mean the Arduino Web Editor (AKA "Arduino Create")?
Please post the exact and complete text of this error you're encountering.
vincescerri:
I accidently touched the 5 volt UNO circuit with 12 volts.
Deleting your account isn't going to fix your broken Uno.
vincescerri:
I've lost control on all my three computers Arduino accounts.
I don't understand what that means. Please explain yourself in detail.