bloody hard drives / viruses

Short story:
Went to boot pc last night - boot disk failure, please insert disk and press enter.

Long story:
Pc has been forgeeting system time last few days, figured was cmos battery (system is 6 years old now, although saying that, it did have a new mobo a couple of years back) or virus. Ran malwarebytes, search and destroy and windows mart qnd s&d found a trojan, couldn't find anything about it online so didn't look serious, still presumed cmos battery. Other than system time, pc runs sweet.
Turned it on last night and got the error. Ripped apart spare pc for its cmos battery thinking that'd be that (spare pc is also around 6 yrs old, but never been used) fired it up, think I got something about cmos defaults, made it to the page which tells you ram and blah, thought it was happy days, it hung for 10 seconds and BAM, disk boot failure.
Reset bios settings not that anything looks out of place, no raid setup and still can't boot.

Now, hard drive shows up in bios, but it could still be dead right?
Tried running Windows disc but kep getting same error, didn't sound like it was spinning even after disabling hard drives in boot sequence.

Plan of action?

 

Sounds like hard drive to me.
Unplug current, stick a random one in. It should post, then give you an OS not found error. That will prove if it's the drive or not.

 

Reset date & time and possible virus just a coincidence then?

 

i would suggest you check power supply to hard drive...make sure its plugged in right at the back...you could have a bent pin?

 

Possibly. If the battery is 6 years old, it's likely it's died. Also possible that the sectors on the drive were failing, which caused corruption, giving a false positive on the virus.
With this type of error it's a process of elimination. Swap out components until it works, usually the easiest if you have spares. Expensive if you don't, and you'd be better off buying a cheap MoBo bundle with a new drive. I have some spare boards and components lying around if you want to make up a cheap replacement, but you'd only be back here again in a year or two.

 

I've got the spares for testing, like I said, replaced battery last night and it just had a new PSU a couple of weeks back, I'll rundown the standard procedures tonight when I've got time

 

it's running!
don't know how!

frenzily backing up.......

 

I uninstalled my other hard drive and all other non essentials and got the error again, so I thought i'd do as sparrow suggested and plug a different hard drive in which was my secondary hard drive and the ****er booted! I must have had them the wrong way round, or bios did, but I don't know how that's possible!
I left cables as they were mobo side and just swapped them between drives, but boot sequence just identifies hard disk, not which individual one, so I don't understand how this worked!
i'm knackered and can't get my head around it, but as long as I can get my stuff off, i'll be happy...