Microsoft has warned consumers that a flaw in its well known Internet Explorer browser could let hackers have access to users' computer.The problem affects Internet Explorer (IE) versions 6 to 11. Even though the targeted attacks to exploit it are limited, the issue may be of special concern to people still using the Windows XP operating system.That is because Microsoft ended official support for that system earlier this month. It means there will be no more official security updates and bug fixes for XP from the firm.