Hi there.
What i have done:

Created a new partition in windows 7
Booted empire efi and then the retail os x disc
Got into install mac menu
Deleted the new partition into a mac (did misstake this for partition)
Now my pc wont boot windows and when i get into windows by using bootdisc the partition handler in windows 7 wont load any partitions so i can reformat the partition back to a windows partition...
what to do?