1st take a backup of disk using Macrium Reflect rescue CD (free). Then Try windows restore or try and restore MBR using Mcrium or minitol partition wizard. Once you have backup of disk image you can reset the windows and restore backup.

humsearshad said:
im facing the same situation right now
i was installing windows 8 Single language in UEFI boot and it didnt let me install saying ''UEFI can only install on GPT partitions
cleaned the disk accidentally while converting it to GPT partition using diskpart 'clean' command, now all the partitions got deleted, is there any way i could recover my data from the deleted/cleaned partitions?