Windows 7 Ultimate Scheduled Restore Size Is Getting Huge?

This query is concerning how Win 7 Ultimate Scheduled Backup works.These are my needs.Often in the past, Windows 7 has become unstable in some way, such that different pgms including Windows Explorer, and other system tools become corrupt. I decide to re-install Win 7 Ultimate 32bit.I have an external 500Gb drive with an Acronis True Image Home 2009 full partition backup on it. The backup is a fully updated, fully game installed backup, and is way faster to use compared to the individual software installations. Since Windows 7 starts acting up about every 3-6 months for me, I replace it.Recently (last restore) I decided to let win Backup and Restore do a scheduled backup every 7 days. I let Win choose what to backup. I intend to let Win be THE backup to use to replace the OS when needed. I have always had problems running out of space where to let Win Backup to on some drives, so I dedicated a 443Gb partition to Backup only. This is on the other half of a 1Tb drive. (I know in some cases it is not wise to use the same drive, but I put all the important things on another physical drive) I have 4 drives, totaling about 3.8Tb. 2 have XP Pro, and 2 have Windows 7 Ultimate. The main C: is 487Gb, with 231Gb used space. The other half of it is N: 443Gb; on which the Backup is written to each week. The size of the backup is now 407.12Gb. The backup on N: is approaching TWICE the size of the used space on the C: drive! And within about a month there will be no more room.I want mainly to retain a pristine Operating System to reload, along with the basic games which are huge. This will save the time WHEN, not IF Windows 7 begins to fail again. (not saying it is a bad or weak OS, just that it fails for me for reasons needing replacement. If only it were as robust as XP has been in the past.)

1. How can I retain a PERFECT OS and games image to use as a basic unchanged original with Win Backup?

2. As Win gets corrupted, how can I know that the latest Backup I might want to restore from isn't corrupt?

3. Can Backup be set to not make redundant Backups that become so huge, yet maintain the original perfect OS and game set, such as a dated incremental backup that can be used to piece together a C: drive again?

4. How do I know that Backup isn't backing-up malware?

5. If I save the latest backup, and the first one, how big should each one actually be?

6. Can I get into the actual backup files individually to decide if I want to restore from them--the options are limited.

7. Win says that it will work "without taking up more than 30 percent of space on the backup disk". Out of a 443Gb drive letter, there is only 33Gb of space left. All done automatically.

8. Is the fact that there is a total of 4 OS's on this computer making the Backups so large? I would assume it is only doing the C: drive, as I would wish, yet something is getting copied over and over, likely. Again, possibility of the latest backup being corrupted is on my mind.

Short of cloning a new disk to replace the later corrupt one, updating it just prior to copying it over, the only other thing I can see doing is to only run the OS on the C: drive, making it easier to replace, yet that has many inherent problems with pgms not working after the OS is replaced, and needing to reinstall anyway.Sorry about the length of this inquiry, but you can see I need assistance.