bootup problem

[Alfred Lorona]

All of a sudden I can't boot up normally. The monitor screen tells me
'invalid system disk. Replace the disk, press any key'.I

I have to press F12 and select my hard disk from the list provided and then
the computer boots up ok.

 

[Richard G. Harper]

Got a CD, floppy diskette or USB flash drive inserted in your computer?
Remove any or all of them present and try again.

 

[Gene E. Bloch]

All of a sudden I can't boot up normally. The monitor screen tells me
'invalid system disk. Replace the disk, press any key'.I

I have to press F12 and select my hard disk from the list provided and then
the computer boots up ok.

Have you (or someone else) changed the boot order in the BIOS?

Otherwise, I go with what Richard G. Harper said.

These two ideas are related...