Lenovo Think Centre Edge PC Tower (Kemptown BN2)

Lenovo Think Centre Edge PC Tower with Intel Core i3, 4GB RAM and Windows 7. Also has a compact disc drive. It switches on but the VGA has stopped working so I've not been able to see it on a monitor. The VGA was working 12-15 months back (the last time I used it) and everything was working fine at that point.