Windows 7 ASUS X5DC Laptop won't boot to Windows 7

[NightEagle]

Recently, my mum's ASUS X5DC laptop crashed under my useage after trying to install Office 365. I did the most common solution by doing a hard shut down and turning it back on.

Next moment the computer wouldn't boot into Windows, it kept saying:

Spoiler: Error Message

Reboot and Select proper Boot device or Insert Boot Media in selected Boot device and press a key

Now this was quite strange. I didn't actually drop the laptop or anything that would cause the hard drive to come out. I opened it up and made sure it was reseated in the ports. I took the hard drive caddy out just to be sure and put it back in to see if it would fix the issue. I booted and it pretty much did the same thing, although it was properly seated in and the caddy was screwed in so it wouldn't budge.

I then checked the BIOS and the most bizzare thing happened. The hard drive AND the disk drive didn't show up on the IDE Configuration screen. The weird thing is that if I selected the Not Detected boxes, they would magically appear, although they don't stay for the boot process, even if I save it after leaving.

This is strange, and I really don't want to reinstall Windows 7 unless I really have to.

Will anyone be able to help me with this?

Thanks

EDIT: Here are the images in order of problem:

 

[bochane]

It looks like the MoBo does not 'remember' the drive.
Could you check the battery on the MoBo, is it flat or are ther contact problems?

 

[NightEagle]

It looks like the MoBo does not 'remember' the drive.
Could you check the battery on the MoBo, is it flat or are ther contact problems?

By what I know, the battery is fully charged and is rarely off the power.

If you mean the CMOS battery then I don't know, although I think its keeping the time. I'll have to look

 

[helpifIcan]

You could also default the BIOS that may help.

 

[NightEagle]

You could also default the BIOS that may help.

Unfortunately I've already done this and its made no difference