From the Windows Recovery Environment you can use the Microsoft command line tools:
diskpart.exe to format partitions.
bcdedit.exe to add or remove windows installations to/from the BCD store.
dism.exe (not to be confused with Dism++ which is from an outside vendor) to restore backups from .wim images and to create backups to .wim images.
These are all command line tools. Using them is error prone (one typo can screw things up) unles you have batch files already for dealing with them. I have only dabbled with them until I found imho better options that work well for me.
You will have to do some rersearch for yourself on exactly how to use these Microsoft command line tools with your system configuration. These are just some more suggestions. As with any other suggestions that will modify your system, use at your own risk. There is plenty of documentation on the internet for using these tools. It is highly suggested that you search for it. There may be some command line tools that are not mentioned here that may help you as well.
In general I find third party tools (gui based) a lot easier to work with than Microsofts command line tools. You will have to do some research on your own, to see what fits your own particular needs the best.
As a LAST resort, since you are pretty much a neophyte in regards to the techniques that I use, you can always reinstall the operating system the hard way by running the OS installation DVD. BUT that should be considered the NUCLEAR option as it would remove your settings, drivers, etc. And basically you would be starting from scratch.
