If you're using a single videocard it goes into the first orange PCI Express x16 slot which is sandwiched between two PCI Express x1 expansion slots. There are three 32 bit PCI slots for legacy devices.

Two IDE connectors, the USB headers and SATA jacks are visible here. The nForce 430 Southbridge is cooled with a small passive aluminum heatsink.

ECS colour coordinates the DDR2 DIMM channels and indicates which slots must be occupied in order to enable dual channel memory. The NF650ISLIT-A natively supports a 24pin ATX power connector however it is still compatible with older power supplies. Just below that is the floppy drive connector.

Here's a close up of those tricky PCI Express x16 videocard locks. If you run two videocards in SLI, don't forget to connect the four pin molex power connector. The nVIDIA nForce 650i Northbridge generates a fair amount of heat and is cooled by a small heatsink fan setup. If you want to replace it, that is possible and there is a three pin header close by. SLi on this board will see each videocard running in x8/x8 mode, not x16/x16.