I'm not 100% sure but windows 8.1 may do exactly what windows 10 preview does
Windows 10 preview when installed Locks the recovery partition so it becomes inaccessible
Again,I'm not sure if 8.1 also did this but I have seen a bunch of threads now on ppl trying windows 10 having the exact same issue and the only response I saw was maybe an Asus certified shop could fix it but Im not certain on it
CoolerMaster HAF 932 Advanced/ Maximus VI Formula/ I7-4770K/Swiftech H320/ Corsair HX850/ G.Skill Trident X (2x8) 16gb 2400MHz/ 2x 840 EVO 120gb(Raid 0)/ WD 1TB HDD (Backup/Storage)/ EVGA GTX 1gb 560 TI/ Asus 12x bluray combo