MCE can be a tricky beast, and even after a successful installation, dependent on what you "do to it", it is quite possible to bring it to its knees if too much "tweaking" is done or the wrong programs are installed.

Experienced people start with a new installation and along the way take "snapshots" of their install to ensure that they they can easily return to a perfect install within 5 minutes no matter what they do to it.

The recommended method is to have the operating system on C: drive on a 10 to 15GB partition along with any programs which you consider a necessity (BRP. Crunchie etc.) and then use a drive image program to take progressive images.  The most common programs used are:

Norton Ghost (commercial)
Acronis True Image (commercial)
DriveImage XML (freeware)

The normal process is as follows:

1. Install Base OS.
2. Install all motherboard drivers, inf updates, nic drivers etc etc.
3. Install all Windows Updates (usually 2 or 3 reboots to do this).
4. Take a ghost image so you can return to this point painlessly.
5. Install Video/Audio/PCI card drivers.
6. Intall TV tuner drivers.
7. Start MCE and go through the wizard.
8. Take a ghost image.
9. Tweak it till happy and working (including adding tv guide and other reg hacks).
10. Take a final ghost image.