I was having problems with my Dell Precision M4500. It wasn't booting:
Windows failed to start. A recent hardware or software change might be the cause. To fix the problem:
1. Insert your windows installation disc and restart your computer.
2. Choose your language settings, and then click "Next".
3. Click "Repair your computer"
If you do not have this disc, contact your administrator or computer manufacturer for assistance.
File: \Status: 0xc000000f
Info: An error occured while attempting to read the boot configuration data.
After panicking that my hard disk was broken, I discovered that this was a problem with the windows boot manager.
So, I made a Windows recovery disk from another Windows 7 machine I had, and tried to boot from that. Didn't work. Same problem. Ah, OK, we'll switch off booting from the hard disk, just boot from the CD. F2 to enter setup on the Dell Precision, sorted.
It took an awful long time to boot from the CD, it's always worrying when that happens. But it boots. The CD says that it's a problem with the boot manager, do you want me to fix it. I say yes. And it does work. It reboots successfully.
First thing to do, install Crashplan and do a backup. Just in case.
Then I switched the boot from disk back on, and reboot. It works. Woohoo.
Moral of the story (two actually):
Make a windows recovery disk, before you need it.
Backup, and test your backups. I've started to use Crashplan (http://www.crashplan.com/). It's great.