Helping people with computers... one answer at a time.
It's tempting to backup to a separate partition because it's somewhat like another disk. The problem is that it's not. You could be risking your data.
I am going to do a clean install of Windows 7 x64 to hopefully fix some errors, which means that I need to back up my files. The problem is that I don't quite have the means to back up my hard drive. Can I simply create a new partition on my existing drive (1TB), copy my files to that, and then perform a clean install on the existing Windows partition? Afterward, I would transfer the files back and delete the "backup" partition. Would that work or am I heading in the wrong direction?
There are risks. In fact, you're running a huge risk without even doing a thing.
Because people often ask if backing up to a separate partition is a valid backup approach, let's examine the scenario in more detail.
What you describe isn't really backing up. You're just moving some files over here so that you can erase that stuff over there.
And, as far as that goes, it's a fine, fine approach. In fact, I'm sure that I've done it myself at some point in the past. It's a fast way to copy some files around so you can wipe out what's on the primary partition and then copy the files back later.
But I'm not going to call it a backup and I suggest that you not think of it that way either.
For how you're using it, it's a fine approach.
This statement concerns me more than anything else:
"I don't quite have the means to back up my hard drive."
So, to put it perhaps too bluntly, you're willing to have everything on that hard drive disappear forever if there is a catastrophic failure?
If so, fantastic. You're good to go.
But I suspect that that's not an acceptable scenario for you. As such, I strongly urge you to figure out some way to do real backups that will cover your assets should there ever be a need.
Backing up one partition onto another where both partitions are on the same hard disk is, at best, only half a solution; at worst, it's a disaster waiting to happen.
It's very simple really: if the hard disk dies, all of the partitions on it go with it. If you've been putting the backups of partition A onto partition B on the same hard drive, then they both disappear at once.
It's like having no backups at all.
Backups on that second partition may be useful for some kinds of errors. Say that you deleted a file that you didn't mean to or that a bad sector crops up on partition A - the backup from partition B would still be there and available to copy back.
But that completely ignores the more disastrous scenario of a catastrophic failure of the entire hard drive and the loss of everything on it.
In case I've not been clear: don't do it.
So, find a way to backup. That's a given.
But when you do so, backup in such a way that you're as isolated from the events that might cause you to need the backup in the first place.
Backup to a second drive, preferably external, to separate the backup from the original hard disk.
Backup to a second drive that you then disconnect, to separate the backup from software "going rogue" on your machine and deleting or corrupting data on all connected drives.
Backup to a second drive that you then disconnect and take elsewhere, to separate the backup from your home in case it's robbed or goes up in flames.
Online backups are a possible solution as well, though they are less capable of handling complete system images or other large backups.
In practice, simply doing only the first - backing up to a second external drive - will get you 99% coverage for most of the problems that you're likely to encounter.