How to make safe softwares?

How to make applications/folders safe. I have lots of data and it was working fine. But now some files are corrupted. So, is there any trick/utility to remain my softwares safe in hdd.
Is there any protection technique to make the softwares fresh?
Answer #1
Safe from what? Hardware failure or other people?
Answer #2
I take it from your previous topics in helpdesk section, you want to safe them from virus attacks (virus modifying header of exe files etc)
you can make an ISO of them or create an encrypted container using Truecrypt and place in them but their will be chance of corruption either by hardware failure or virus attacks.
As for installed application only way is to use antivirus along with firewall and good antispyware
Answer #3
I mean that antivirus make the software bad during scanning. So, making ISO can protect the files?