MSI P45 Neo3 Startup Beeps 4 times

I'm a noob to Tom's hardware, so please be patient and help?

Just got a new MSI P45 Neo3 motherboard with an Intel E8400. When it starts I hear four beeps whilst the motherboard splash screen displays. The first three beeps are maybe 1 full second apart each, with the fourth beep coming about 1½ to 2 seconds after the first three?
However, the PC continues to boot just fine into Vista Home premium 64 bit, and all my software seems to work OK.

So is this unusual startup beeping a problem, and if so, what might it be? And more importantly, when is the solution?

I tried to press "tab to post" as soon as the motherboard startup screen appears, but by the time it recognises the keypress, the beeps have finished. Plus, the resulting text displaying devices etc goes so fast I can't read it anyway.

ALSO:
I installed the supplied chipset, network card, and onboard sound card drivers for vista from the supplied CD, but did not install the RAID drivers as I only have one hard disk, so RAID is not required. However, the windows device manager shows the motherboard "video controller" has no drivers (I'm running a GeForce 8600 GT, which has it's own drivers and works just fine).

All help welcome.
Thanks.

P45 Neo should give one beep then x quieter beeps where x is the number of USB devices that you have connected.