Make sure that you are using the latest version of VMware player, only the latest version supports Windows 8, also give at least 20Gigs of hard disk space and 1Gig of memory.
VMware Player 4 does not officially support Windows 8, but I have been able to install Windows 8 to a VM running within it. Only thing that didn't quite work properly was VMware Tools. The OS install went fine though.
if you have an older processor without virtu I believe, it won't let you install the 64 bit o/s in VmWare player. I tried that myself with Windows 8 on an Intel Core 2 Duo and it would only let me install the 32 bit version in Wmware Player. It did let me install the 32-bit o/s of Windows 8 though.
The OP stated he/she has a Core i5 chip (@ the OP, it would be nice to know exactly what model of Core i5 you have though). I am 99% sure all Core i5 chips support the Virtualization feature - but there are 74 chips carrying the name Core i5 and I haven't checked them all. Again @ the OP, this is your cue