I had the same problem. If you are not able to format, not able to scan for errors or get too many error messages like operating system not found, code 88 hard drive not found, blues screen errors
you have a bad hard drive. Take the hard drive out, if you have any files that you don't want to loose try to get USB to IDE adapter. It is not guaranteed that your hard drive will be recognized on another computer (supposed to work just like USB drive), but be patient, try different computers too. The time to initialize may vary from under a minute to 20 minutes with bad drives. See if it will allow you to copy files (it did allow in my case).
Next: take the hard drive to any computer store and ask them to check it for you. If they say the hard drive is bad get a new one (they have the same USB to IDE harddrive, but they also have a lot of software and a lot of experience).
Get a new hard drive and order restoration CDs from SONY. When use them on the new blank hard drive you will get an error message, ignore it and use the advanced option as recommended.
The restoration CD that I got from SONY was only $20 and it did install my OS from the scratch along with all the software. The restoration CD will work only with your model. Sony support told me that restoration CD is not assigned for the new hard drive...well they don't know a shit.