PXE-E61 and PXE-M0F errors on startup; OS not found.

Hi,
I installed WindowBlinds 5 on my laptop last night and played around with a couple of skins. I restarted a couple of times to update settings etc. then went to bed. This morning I turned it on and I get:

PXE-E61: Media test failure, check cable.
PXE-M0F:Exiting PXE ROM.
Operating System not found.

A quick google search brought up a number of similar problems, most of them fixed by changing the boot order or disableing network boot. Doing this for me just removed the first two lines, now all I get on startup is:

Operating System not found.

What happened? What did WindowBlinds do to my computer?!?

P.S. In Bios HHD Model Name: None and HHD Serial Number: (looks like very faint japanese writing or something).

Thanks for any suggestions in advance!

 

Just a quick addition to this post. I just reseated the hard drive and the error persists. Could the hard drive have failed? How would I check to see whether the hard drive has failed?