Boot problem with Win 7 ("Missing Operating System" Error

[CraigHarrison]

Today morning I powered up my PC and it got through the Motherboard Splash Screen, Seemed to startup properly and then I got this message in blocky white letters on a black background "Missing Operating System"
I cut the power cause it didnt seem to be going anywhere and then powered up again
I got the same problem
cut power and started again this time I entered into BIOS and looked at the HDD to see if there were any problems
It looked ok
then i looked at the boot sequence and changed it from
HDD
CD/DVD
Other

to

HDD
HDD
Other

and booted again
This time it booted into windows perfectly

I would really like to know what this problem might be
Is it a virus ?
or a symptom of HDD failure ?
any help would be much appreciated
Thank You

 

[nikorr]

Well, u don't cut the power. Try the reset button first.

What is the mobo?

 

[mcnumpty23]

make sure you didnt leave a cd/dvd in the drive

 

[CraigHarrison]

Sorry ..Thats what I meant ..words failed me :/

 

[CraigHarrison]

make sure you didnt leave a cd/dvd in the drive

Never had problems before with DVDs in the drive
Anyways ill do that and see
thanks