I have 4 primary partitions already, and I want to make a partition for installing ubuntu, but I get the error that there can't be more than 4 primary partitions, is there a way that I can put two of the existing partitions inside an extended partition, without loosing any data? Edit: all the partitions are NTFS.
Since you haven't installed Ubuntu yet, and still on windows then you may want to take a look at this. EaseUS.
It will allow you to do the conversion without loosing any data, and its free