I hope I'm posting this in the right place. I'm new here. My husband and I are trying to fix my parent's almost 2-year-old HP AMD 64 desktop computer that was running Windows Vista 64-bit. A few days ago, my dad went to turn the computer on and he got the error that windows failed to start. I tried my best to help him fix it over the phone, but nothing that we tried worked. The next day, my parents brought the computer over to our house and we figured that we would just format the hard drive and do a fresh intall of Windows 7 Ultimate since we were planning on doing that for them soon anyway. We put in a windows 98 boot CD into the DVD-RW drive and ran F disk and fomatted the drive without a problem. We then put the Windows 7 Ultimate disk in and rebooted the computer. Instead of getting the expected "press any key to boot from CD" message, we got a black screen with a blinking cursor. After several seconds, we finally got the message "invalid system disk. Please insert disk and then press any key." The Windows 7 DVD (NOT a copied disk) was already in the drive, so we pressed a key and got the message "Disk boot failure" We then tried another Windows 7 disk and got the same error. We then tried a Windows Vista and even an old Windows XP disk, but we got the same errors with those disks as well. We know that these disks are all good. We tested them on our own computers and have used them to do installs before. Yes, we have the bios set to boot from the DVD-RW drive first and the hard drive second. There is no floppy drive in this tower. We finally just assumed that the hard drive was the problem, so my parents went out this afternoon and bought a brand new Western Digital 500 GB SATA drive and brought it over. My husband put the new drive in, made the partition, and put the Windows 7 disk in again, but we still got the same disk boot failure error! So, we now know it's not the hard drive and my parents just spent $70 on a new hard drive for nothing, although it is much bigger than the 250 GB that they had in there. My husband and I are usually great with computers, but we are totally at a loss as to what could be going on here. We have never seen this before. Why do we keep getting these disk boot failures? It's not even giving us an option to boot from the CD like it should be doing. It can't be the DVD-RW drive since it read the 98 boot CD just fine, but for some reason it's not reading any of the windows disks. Any ideas? Please help! We're desperate to get this fixed ASAP!