1. Insert the Windows 7 installation disc or eMachines system restore disc into the optical drive of the computer. Shut down the PC.
2. Restart the computer. As soon as you see the eMachines logo, press the 'F12' key repeatedly until you see the 'Boot Menu.' Use the down-arrow key to position the cursor over the CD-ROM option, then press the 'Enter' key. Press a key on the keyboard when you see the 'Press any key to boot from CD' message.

3. Click the drop-down list on the Windows Setup screen and select your preferred language. Review the time and date settings, and use the on-screen controls to change them if they are not correct. Click the 'Next' button.
4. Click the 'Repair your computer' option. Click and select the 'C:\Windows' option in the list, then 'Next.'
5. Click the 'Command Prompt' option in the 'System Recovery Options' dialog box. Wait a few minutes for Windows to load recovery utility files from the installation or recovery disc, and to display the Command Prompt. The Command Prompt is similar to the DOS prompt in older computers, and does not have a graphical interface -- just a black screen with white type.
6. Type 'Bootrec.exe /FixMbr' at the Command Prompt and press 'Enter.' Windows repairs the partition table and reboots the computer. If the 'Cannot rebuild Master Boot Record' error appears, type 'Bootrec.exe /FixBoot' at the Command Prompt and press 'Enter.' If you still receive a Master Boot Record errors -- error codes and messages may vary -- type 'Bootrec.exe /RebuildBcd' at the Command Prompt and press 'Enter.'