|"mboard- intel desktopboard"|
There are dozens of "intel desktopboards", if not 100's.
"Video card-palit geforce210 1 gb"
Hopefully you don't expect to play games because the 210 is NOT a gaming card.
"i've also installed a new fan"
I'm guess you mean CPU cooling fan? Did you apply the thermal paste correctly?
"u are suggesting dat i should format and reinstall my os(win7)"
No dat is not what he means. And what's up with the text-speak? Please type out complete words. And pay attention to the responses you're getting - you were told to do a "repair installation". If you don't know what that is, google it!
"i can hear 2 short beeps before booting"
If it's a modern board, 2 beeps = No video detected.
If it's an outdated "legacy board", 2 beeps = Parity cannot be reset (in other words, RAM problem).