Windows failed to start?

So I tried to install a game demo, which finished then asked me if i wanted to restart the computer, so I did. When it starts up it says:

Windos failed to start. A recent hardware or software change may be the cause. To fix the problem:

1. Insert your Windows Installation disc and restart the computer
2. choose your language settings, then click Next
3. Click "repair your computer"

File: \Windows\System32\drivers\sfsync.02.sys

Status: 0xc0000428

Info: Windows cannot verify the difital signature for this file.

If I put in my Vista disc then it comes up with another screen asking If I want to run in Safe mode, run normally etc.

My keyboard won’t work on this screen so I can’t select anything!! What do I do? I really don’t want to have all my stuff wiped so please help…
I would try to do that but my keyboard won’t respond when the screen comes up, so I can’t select anything.

my aunt asked me to install Windows Vista Home Premium on her comp.,she had XP and it saysWindows Vista capable.When Installing I selected the Upgrade option instead of doing the clean installation. no problems installing,but afterwards everything is running slow. Ibrought the my house to use dsl &installed all the the windows updates in hopes that it would solve the slowness. When that was done the computer restarted itself &said it was configuring the updates & then when I came back to check on it Windows Boot Manager was on the screen saying:
"Windows failed to start. A recent hardware or software change might be the cause. To fix the problem:
1.Insert you Windows installation disc and restart your computer.
2. Choose your language settings, and then click NEXT
…File: \windows\system32\winload.exe status: 0xc000000f

When i put the vista or the hp reinstall disc in nothing happens. PLEASE help I really dont want to lose everthing. THANKS.
I can’t get past the Windows Boot Manager, I tried pressing F8 to try and get it back to last known good configuration, but pressing F8 doesn’t do anything. I’d be happy if I could just get back to the XP version so she doesn’t lose any of her programs, and then trying to re-install Vista while connected to the internet.

We apologize for the inconvenience, but Windows did not start successfully. A recent hardware or software change might have caused this.

If your computer stopped responding, restarted unexpectedly, or was automatically shut down to protect your files and folders, choose Last Known Good Configuration to revert to the most recent settings that worked.

If a previous startup attempt was interrupted due to a power failure or because the Power or Reset button was pressed, or if you aren’t sure what caused the problem, choose Start Windows Normally.

Safe Mode
Safe Mode with Networking
Safe Mode with Command Prompt
Last Known Good Configuration (your most recent settings that worked)
Start Windows Normally

^^^ that is what i get when try to start my computer. no matter which option i try they all send me back to that same screen. I don’t have my windows xp cd to repair it or do whatever the cd is needed to do. anything i can do to fix it without the cd?

Brand new Asus model X83V. Had it for about 2 weeks. I turned it off (properly) and left it alone for about 2 hours. When I turned it back on "Windows boot Manager" came up with the following message;

"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."

File: \Windows\system32\kdcom.dll
Status: 0xc0000098
Info: Windows failed to load because the kernal debugger DLL is missing, or corrupt"

I have not installed anything since 2 weeks ago. I do not have a Windows disc. I have a recovery disc, but if I run that I will lose my pictures. My pictures are super important to me. I would lose all the pictures from my daughters birthday, among other important pictures I just can’t lose! Please help!

Can you help me fix my laptop?

Help, please! My laptop (Toshiba equium) isn’t working and I have no idea why. It has so much of my work on it and im desparate to get it up and running again, if any one can help I would be so so grateful.

It comes up with this on start up –
Windows Error Recovery
Windows failed to start. A recent hardware of software change might be the cause.

If windows files have been damaged or configured incorrectly, Startup repair can help
diagnose and fix the problem. If power was interrupted during startup, choose start
windows normally.
(use the arrow keys to highlight your choice.)

Launch startup repair (recommended)
Start windows normally

If I choose ‘Launch startup repair’ then it comes up
‘windows is loading files…’
then a loading screen then a window comes up saying –
‘startup repair is checking your system for problems…’
after just a couple of seconds this disappears and then a window that says
‘windows cannot repair this computer automatically’ comes up with theses options –
‘view diagnostic repair details’
‘view advanced options for system recovery and support’
And ‘cancel’

If I choose ‘Start windows normally’ then a load screen appears for a few seconds before it simple restarts and goes back to the ‘Windows error recovery’ screen.

Please help.
The diagnositic repair retails are miles long, to long to type out.

I do not want to lose my information, I have important work on my laptop – please help.