If your computer is like my G55VW, it came with Windows 8 (no Pro or Home or anything).
This complicates a fresh install of Windows 8.1 slightly, since Microsoft in it's infinite wisdom made it so that Windows 8.1 install media won't recognise a Windows 8 key embedded in the uefi firmware.
You'll have to use a install key (you can find these directly from Microsoft by googling), which will allow you to install Windows 8.1 fresh. And once this is done, your new Windows 8.1 install will use your embedded key to activate properly.
I'm unsure if the forum rules permits me to link to this key so I won't, but they're something Microsoft have released as an official workaround for this blunder so google should be able to help out.
There're also programs out there capable of reading your key from the uefi. But this won't help either since the problem is that the W8 license key is not valid in the W8.1 installer. Only works after installation for activation. And the skip license input button in the installer was removed after W7 hehe.
Asus ROG G55VW:
CPU: i7 3630QM
GFX: Geforce GTX660M with 2GB ram
RAM: 2x8Gb 2133MHz Kingston HyperX Impact (surprisingly the G55VW uses the 2133 X.M.P. profile)
Storage: RAID0 with 2x 256Gb Crucial SSDs (both msata, one in a sata adapter)
OS: Windows 10 x64