OK Let's try this

Navigate to the following registry key:

32-bit Computers: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Microsoft SQL Server\MSSQL.1\Setup

64-bit Computers: HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\Microsoft SQL Server\MSSQL.1\Setup

Locate the Resume REG_DWORD entry on the right pane.

Right click on the Resume entry and select Modify. Change the Decimal value from 1 to 0 and press OK.

Then

32-bit Computers: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Microsoft SQL Server\MSSQL.2\Setup

64-bit Computers: HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\Microsoft SQL Server\MSSQL.2\Setup

Locate the Resume REG_DWORD entry on the right pane.
Right click on the Resume entry and select Modify. Change the Decimal value from 1 to 0 and press OK

Then try to update and see whether that works

Hope this helps,
Captain