HP ProBook 4545S 15.6" AMD 320GB Laptops

Can someone from WOOT verify if this is one 4GBs ram stick or 2x4 GBs?

Unfortunately, no. Per the buyer, with refurbished computers, it can vary from device to device.

is Windows 10 included - or do i need to purchase a key card/code. thanks

Windows 10 is preloaded. No additional purchase. Windows 10 stores the product key in BIOS.