FireSoul

If its a multipart zip file if you just extract one they will all extract (if you see what I mean)

Looks similar to my old seerrver room but we had cabinet 1 moved so it was against the wall with cab 2 next to it. I assume the front of ther servers will be facing away from the door (i.e. towards the air con)?

You won't be able to install any 6.x version as Apple are no longer signing any iOS other than v7.0.4. If that phone has already been jailbroken and the SHSH blobs have been saved (to Cydia for example) then you may be in luck, but the chances of that are slim to none. You'll need to wait until the 7.0.4 jailbreak is released (if it ever is).

Just flash it with whatever the latest version is, it'll replace whatever was already on it. Apple are no longer signing older versions anyway so putting an old iOS on isn't an option anyway (I'm assuming you're not wanting to jailbreak it)

I'd guess it was a failed iOS 7 install. Just plug it into iTunes and restore to whatever the latest iOS version is.

More than lkikely it'll just need restoring. If it was very cheap I'd probably take a punt on it. Putting it in DFU mode and doing a firmware restore should fix it. The only concern I would have is that the former owner may have reported it stolen and therefore had the IMEI blocked.