With some systems you may have to change a bios setting if you need to use USB and safe mode. I prefer using PS2 as I need all the USB ports I can get, I am using 7 at the moment which only leaves me 1 spare.
My motherboard Click Here has a single PS2 port half green and half purple to take either a mouse or a keyboard. Not being a fan of wireless keyboards but liking wireless mice I use the PS2 for the keyboard and USB for the mouse. Like wiz-king I keep as many USB ports as free as possible.
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