Restore Points are held in reserved portion of the hard drive which is set by default at around 15% of the total drive capacity which is not user-configurable. As new restore points are created, the oldest one is deleted if reserved space is all used up - that's just the way it works I'm afraid.
The only way to preserve a copy of a 'clean' and fully working installation is to use disk-imaging software to create a "snapshot" of everything currently on that partition, including the boot files. You can then keep this snapshot image safe on a separate partition (and preferrably on a separate hard disk altogether) so you can fall back on it following just about any type of catastrophy including total failure of the hard disk on which Windows is installed.
Disk-imaging software is avialble free as well as commercial versions which have more features for power users.
Free ones that I know of (and which I've used myself) include:
Paragon Backup & Recovery Free Edition: http://www.paragon-s...ome/db-express/
Macrium Reflect Free: http://www.macrium.com/ReflectFree.asp
EASEUS Todo Backup: http://www.todo-backup.com/
If you are willing to pay (USD 39), I can highly recommend one above all the others as I currently use it myself and it's so simple to use and totally reliable.
It's called Active Disk Image
There is no free version as such, but you can download a free trial version before you decide to buy it.
I bought it without hesitation. The licence permits you to install it on up to 3 computers, so I've used it to back up all three machines in my family. I tested every backup image and it fully restored every system without fail.
Edited by phillipcorcoran, 09 July 2010 - 05:21 AM.