That motherboard has a floppy connector on it. One accessory is:
1 x FDD cable
Kinda silly to put it in the box if there is no port to use it in.
The thing about floppy is that they can't really get rid of it... One of the advertised features of SATA hdd chipsets is the ability to do software RAID. This RAID has to be configured before the OS is installed. Windows will ask during setup if you want to load 3rd party RAID drivers... from a floppy! So, they can't advertise the RAID capabilities of their motherboard unless they include a floppy connector.
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Motherboards are all standardized in size (or at worst, a smaller mobo will fit in the standard format for that size class, with the screw holes placed at the correct place). A
microATX motherboard will fit in regular sized computer cases, as well as mid-towers and full-towers. If you feel you will need more expansion slots than are provided by the motherboard you linked to, you will probably need to get a full-sized
ATX motherboard. With an ATX motherboard, you have to pay more attention to case size, since there are small cases that cannot hold ATX motherboards. Larger cases will hold them without problem though.
If you want to make sure, open up your case and measure the physical dimensions of your current motherboard. If it is around 244 mm × 244 mm, to a minimum of 171.45 mm x 171.45 mm in some cases, it is microATX. Full sized ATX is 305 mm × 244 mm.