Recently, 3 days ago, following a windows update, I rebooted my win 7 64 bit but it refused to reboot and has the DOS screen indicating "I/O error". First I thought it was a hard disk failure, after doing a lot of disk checking, I restored to last point before the update and I managed to reboot my machine. I disabled automatic update and did a manual windows update, 2 out of the 13 or 14 patches failed with 80007......error code. I understood that it might be permissions issue and might be caused by an Anti-virus. I removed AV did reboot, did again windows update and it worked fine, all patches were installed. Rebooting again for the 1st time was OK, then I needed to reboot again to double check, I had exactly the same error "I/O" error. Not having another option, I inserted the win 7 rescu CD again keeping in mind to do a restore, I forgot to hit any key to boot from CD, to my surprise machine started normally. I gave it another try, the same thing happened exactly, without the CD inserted I get the I/O error, inserting it the machine works correctly

use a different SATA cable or connect the HDD to a different SATA port of your motherboard."A programmer is just a tool which converts caffeine into code" CLIP- Stellvertreter http://www.winvistaside.de/

Thanks Andre, I will give it a go and let you know. Alerts seem not working, I am subscribed to this thread in order to receive alerts once there is a new response. Who can look and fix this issue.