1) You can download and try
aomei backupper free (I'm using the pro, got it from bitsdujour.com as giveaway, and it saved my but..ehm, machine a few of days ago).
What it does? It allows you to create a copy of your system configuration/partitions in one big file (mine are about 11-15GB), and you'll put that (those) file(s) in a safer place (another healthy hard disk, usually).
You can choose only the important partitions and exclude data partitions, or you can include all partitions (but the file will be bigger).
In case something bad happens, you'll be able to use the most recent system image to restore your partitions in few dozens of minutes (or minutes, if you have a faster pc than mine...).
To do it, you'll need to create a cd/usb drive with the software in it (
it should be created just after you installed the software, so you'll test if it works and, if yes, you'll know you can use it in case of problems), to start windows directly with it.
2) You can use the search function in control panel: type
create recovery in it, or only
create and control panel will show you that you can create a recovery cd directly from your machine (There are many tutorials on the web, if you need one).
You can also create/download your windows 7 installation disk from
Download Windows 7 Disc Images (ISO Files) (click) (I think it works only with retailer licenses, and not with OEM licenses, but I'm not totally sure).
After you have downloaded it, it should be mastered/burned on a cd/dvd (I can't remember/know its exact size), and test if it works.
Question: How big is the danger if I try it without the CD?
I believe it's a very simple task and that there are no risks, but who knows...