Had encountered similar problem.

http://buruguduystunstugudunstuy.blogspot.com/2007/11/day-haldll-made-my-day.html

Hope you'll have luck as I did. BTW, before doing anything, its nice to always backup. Use a bootable cd.

If all else fails, reinstall (remember, you should have backup). VAIO can reinstall its OS considering you have not formatted the partition. Upon bootup, press F10 and follow the wizard. Everything will be as good as new.