Error loading operating system - Seagate Barracuda 7200.7 40 GB Hard Drive

What operating system? Windows? If so, what version? Linux? Mac?

It could be a corrupt system file or a corrupt section in the MBR of the drive. If you have critical data on the drive that needs backed up, then I recommend that you (from another machine of course) download a live cd version of linux to boot into along with an external usb hard drive. You can then mount your existing drive and copy your data to the external usb drive for a backup of data. I would recommend either PclinuxOS, Knoppix or Puppy Linux. Exit once backup is complete.

Next, boot your machine with either a restore disk received with the purchase of your computer, or if unavailable, boot to a system disk of your current operating system (such as windows xp, etc.). This MIGHT require a fresh install of the operating system - thus the reason for doing a backup of data first. If however, there is a bad sector in the drive's MBR then you're ultimately looking at replacement of the hard drive and then performing a restore or a fresh install of the operating system.

If you find this solution to be helpful, then please take a moment to rate this post. - Thanks.

I have worked for at least a month during every spare moment using every idea I could find to rescue files on a 500 GB Seagate FreeAgent Go external drive. Nothing worked to resolve I/O errors and incorrect parameters. For the last week, I have looked at many more answers. Last night I found one that said Knoppix may allow me to see and download the files with these errors. After several tries this morning, a bootable DVD with the .iso worked! No, it did not work with my WIN 7 laptop. I was able to boot up to Knoppix on an old WIN XP laptop. The FreeAgent drive could not be opened in Knoppix. I think "read error" was the message. I was again contemplating giving up as Knoppix shut down. The drive was still connected via usb on reboot! i had not yet tossed it out and am I ever glad! WIN XP began to read the drive! It is currently being backed up using the faster Win 7 laptop!