Which backup & restore to use

do I have to completely wipe my external drive clean before starting any new backup procedure

No, backup image is stored as a file.

can I store both system image & data files on the external drive without creating paritions

I think you mean extra partitions - you must already have at least one.

Yes, just store it like any other file.

is my external drive big enough to hold everything

Depends how much used space you have on the source partition. Also depends on what type of files you have on the used space, some will compress a lot, some file types compress very little.

Images will typically be 50-60% of the size of the original used space.




Aomei ( owmay ) Backupper is the best free imaging program, Standard version is free:

Windows 8.1, Windows 8, Windows 7 Free Backup and Restore Software

Many people here prefer Macrium Reflect Free (here is a good tutorial on how to use Macrium Reflect). I use a paid version of Macrium Reflect to back up my C: drive (or partition, depending on the machine) but the free version will meet most peoples needs. I also use FreeFileSync to back up my data drives (or partition, depending on the machine). A folder/file syncing program, such as FreeFileSync is much faster for backing up data than imaging. The OS and programs, however, have to be backed up by imaging or cloning, imaging generally being the most practical.

For some redundancy, I use 2 system imaging programs; Windows inbuilt and (free) Macrium Reflect. Neither has let me down so far but Macrium has the edge. Macrium is more flexible and does provide compression of your image files. For hardware redundancy I keep current images on 2 separate external HDDs.

Which disk do you mean - the one you intend to store your images on?

Up to you. If what you have on there is not accessible or not wanted, then you can do a quick format if you like. Or you could just delete anything you are certain you don't want. 50gb isn't a lot of space, so if you can clear some more, it is a good idea.

If you want to do regular file backups as well as an image, then aomei does that also. Schedule it if you like.

Yes. good idea. Quick format will be fine to clear that if you don't need/want anything currently on there.

Macrium and Windows built in imaging.

Even though I haven't used it myself (I found it too confusing when I first tried to) after seeing all the posts from people having problems with Windows Imaging, there is no way I would ever recommend it, especially since Macrium Reflect is so easy to use and is so reliable.