SATA Drive not found.

[eno]

Here's the sequence of events

1. Computer worked fine yesterday no sign of virus etc.
2. Powered down properly last night.
3. On power up this morning runs through the bios ...... freezes... after 20 seconds comes up with Drive0 not found: Serial ATA, SATA-0 strike F1 to continue F2 for setup
4. F1= message no boot device available ...... F2= normal setup bios sees the drive