Okay, I've had a look around for solutions, but I have ran out of ideas. I installed Ubuntu 12.04 a week or so after it was released, other than a DNS issue right at the start which was easily resolved, it has been working perfectly.

A couple of days ago it suddenly started hanging on boot at the purple screen (right before the ubuntu icon splash screen mabob). It doesn't hang permanently however, maybe even less than a minute, but it is noticeable. When it does boot and I log in, the display setting on my laptop screen is consistently borked up, you can go and change it by hand, which works, but it will revert to borkage upon reboot. My second monitor has the correct settings still. Now as far as I am aware I haven't updated anything recently, but I can't be 100% certain (something has obviously changed, I trust the evidence more than I trust my memory). I have update since this happened though, hoping it would magically fix itself.

I ran gksu diagnose and get two error messages:
ACPI_OSC request failed (AE_ERROR)

and

warning at /build/buildd/linux-3.2.0/kernel/watchdog.c:241 watchdog_overflow_callback

The first I found info on, suggesting this wasn't anything for me to worry about, the second I can't find anything on that means anything to me.

The issues themselves don't actually bother me too much, but something caused them, and I don't like not knowing what.

Any help would be massively appreciated, I will even name a puppy in your honour if I ever have a puppy (and it doesn't already have a name, or your name is stupid).