Why does my monitor blink?

ive bought a new computer recently and my monitor keeps blinking randomly,, not often but like 2wice a day ? at random moments..

i dont think its the monitors fault coz i used it wid my previous comp and this neva happend..

i thought i didnt plug it in either but its not tat also..

friend told me it mite b that i needed 2 update my video drive and tat wasnt the problem either..

so wat is wrong ??