Did you try entering "3" at the prompt to Repair your computer?
Got this off Emachine's page:
Windows Recovery Environment (WinRE) on Windows Vista Backup Media
The Windows Recovery Environment (WinRE) can be used when troubleshooting issues where the computer cannot boot into Windows. It can be used for automatic diagnosis and recovery using Startup Repair, or it can be used to manually recover the computer using the tools available from within the environment such as the Registry Editor or System Restore.
1.Place the Windows Vista operating system disc in the optical drive. Close any dialog boxes that open.
2.Restart the computer.
Note: The computer must be configured to boot to the CD/DVD drive.
3.After the Gateway/eMachines BIOS logo appears, when prompted, press any key to boot from CD or DVD.
4.Windows loads files.
5.In the Install Windows dialog box, select the appropriate information, and then click Next.
6.In the Install Windows dialog box, click Repair your computer.
7.In the System Recovery Options dialog box, select the appropriate operating system, and then click Next. If controller drivers are needed, click Load Driver
8.In the System Recovery Options window, select the appropriate option.
From within the Windows Recovery Environment there are a variety of tools that can be used for troubleshooting:
?Startup Repair - Can be used to automatically diagnose and fix problems that are preventing Windows from starting. These problems could be registry corruption and missing/corrupted/damaged system or driver files. It can also diagnose some hardware failures.
?System Restore - Restore Windows to an earlier point in time.
?Windows Memory Diagnostic Tool - This tool checks your computer for memory hardware errors. For additional information on how to use the Windows Memory Diagnostic tool see the Tools and Troubleshooting - Memory Diagnostic Tool document.
WARNING: Read this carefully, and completely!
You really do not want to do the following unless you pull the drive, and use an external case to get the data off the drive. This means you need another computer to store your data files on that already has an external drive. You'd copy your data to that external drive, use PC Recovery to start fresh (complete re-install of OS, like the first day you bought the computer). Then put the drive back into the Emachine, and do the Restore. Finally, you'd use hookup the external drive from the second computer to copy back your data. UNDERSTAND that you'll loose all your installed programs, settings, email, and games. The Emachine would be as DAY # 1.
?Complete PC Restore - Restore a system-level backup. This assumes you have done a Complete PC backup prior to attempting to use this tool. This backup point could be stored on DVD/CD discs or a local hard drive.
Note: This option is only functional within Windows Vista Ultimate.