So heres what happened. I've been running Windows XP 64bit on my newly built machine using a 120GB HD. As a backup, I also had a 160GB HD. After a while, I decided to use my student Windows 7 download through my college, so I got Windows 7 Professional 64bit and it came as an .EXE installer package.
I ran this package and installed it to the empty 160GB HD formatted and all. I was then able to dual boot Windows XP and Windows 7. In the last week, I decided I no longer needed XP so I would free up the space. I deleted as many files as I could via trashing them (music etc), then chose to insert my original XP cd and delete the entire partition, which I did.
Once the XP partition was deleted and I had all 120GB free, I hit F3 on the CD (quite) and it restart, only to see the "Disk Boot Failure. Insert System Disk and Press Enter now". Weird...I figured maybe my boot order was screwed up or my jumpers. I switched both, now my 160GB Windows 7 drive shows as master and the empty 120 as slave, yet I still get the message.
I've taken the CD out of the drive. I've even disconnected the CD drive and the slave HD. I still get the same error. Could there have been important files on the XP HD that kept 7 running that I deleted? Am I just an idiot and it's a BIOS issue?
Thanks so much for the help, sorry for the muddled question, I'm just a bit disappointed at the moment.
when you use delete option with xp setup it may altered the MBR, because xp is pretty older version & wont recognize newer OS so you installed Windows 7 after installing xp..so the xp partition will have the MBR & you deleted it with xp setup.. then how the system knows about your OS & it location in HDD without MBR.. try to use recovery console in win 7 using boot from your win 7 dvd..
I have a suspicion this is linked to how Win 7 established the Dual Boot feature. You did the Win 7 installation as you should, and that included having it install on the 160 GB unit a file with info on BOTH bootable hard drive units so it could find the OS you choose at boot time. But later you decided to destroy all the stuff on the 120 GB HDD. Now when it starts to boot from the 160 GB drive, it goes looking for that alternative OS on a bootable 120 GB drive and - DAMN! its not there! That's a Disk Boot Failure because the 120 GB drive is no longer bootable.
I would start looking into how you undo a Dual Boot setup in Win 7. Especially try to find a way to remove that feature when the second drive is no longer available.