There's an ever so small chance that it just got removed from the CMOS configuration, but the more likely scenario seems to be the drive was dying and has now died. The stress of the defrag and disk scan was probably enough to tip it over the edge.
You can try pulling it out and sticking it into an external enclosure. If you get it to load up, pull any important data off of it immediately, because you may never get it going again.
My niece never had any security for long time.I put spywareblaster
and windows defender,she put e-trust a few days ago.She never has defrag
or check disk for errors.It is dell laptop Inspiron 1100,256mb mem.XP
home Intel Celeron 2.00ghz.I defraged it and checked for errors and bad
blocks.It never came back on.It says primary hard drive not found.No
boot device avalible .I tried to reload factory disk,it said-setup did not find any hard disk drives installed on your computer.
Make sure any HDD are powered on and properly connected to your computer
and that the configure is correct.Please help they think I screwed it up.But I can not see how.I believe it was on it's way.Anyway I feel
resposible.Thanks for any advice in advance!!