Random beeping sequences at startup

My old computer always had a more or less random sequence of beeps when starting up. Last week I bought new components (mobo, gpu, cpu, psu, ram) and this new computer also gives random beep sequences at startup.

Some sequences are:

high-beep / low-beep / low-beep / high-beep high-beep

high-beep / low-beep / low-beep / high-beep

high-beep / low-beep / high-beep / high-beep / low-beep

high-beep / high-beep / low-beep


My specifications:
AMD Phenom II x4 955BE 3.2GHZ with stock cooler
MSI 790GX-G65
2x2GB Kingston DDR3 1333Mhz RAM
Sapphire HD4890 1GB
OCZ SteathXStream 600W

Everything is stock and not overclocked.

Let me add that I don't have any problems with the pc, it runs fine, no crashes etc.


My previous system which also had random beeps:

AMD Athlon x2 4200+ 2.2Ghz with stock cooler
MSI K9N-Neo v2
2x1GB Kingston DDRII 800mhz
8600GT 512mb
450W powersupply