What needs to be done is to let that disk check complete. However, it can't do that now that it won't boot so it will have to be run from a cd. Unfortunately, the Gateway cd's do not provide for this option.
Download
RC.ISO and burn it to a cd as an ISO image. You may need a burning toy like
ISO Recorder to do this...be sure to get the version for the operating system installed on the machine you will be using to burn the cd.
Insert the RC.ISO disk into the CD-ROM drive, and then restart the computer.
Click to select any options that are required to start the computer from the CD-ROM drive if you are prompted to do so. Watch for the prompt to "Press any key to boot from cd"...when you see that prompt, press the spacebar.
When the "Welcome to Setup" screen appears, press
R to start the Recovery Console.
If you have a dual-boot or multiple-boot computer, select the installation that you want to access from the Recovery Console by number (usually 1).
When you are prompted to do so, type the Administrator password. If you have not set a password, leave it blank and press "Enter".
At the Recovery Console command prompt, type
chkdsk /r and press "Enter". (Note the space before /r)
This will start a very long check of the file system. Be patient...let it finish. It may appear that the check hangs or even back up a few times...this is normal. When the test completes and you are again presented with the command prompt, type
exit and press "Enter"...the machine will restart. Let it try to boot normally...do not boot to the cd this time.
Let us know if this gets you back into Windows.