are you a good PC troubleshooter? help here!

[energizerz]

=> power light= On, HD light= On then after a few seconds it turns off.. Monitor light= standby mode.(yellow light flashing.. Keyboard= No light...
i want to know what cause this thing to happen.. coz my only solution to this thing to make my system run again is to remove the cpu and clean the thermal paste

put back the cpu and the heatsink,then plug the system.(Still the same with no keyboard,etc) then remove again the cpu put again thermal paste then plug again
the system then it will now run fine.. any idea what is faulty there? coz im tired doing it everytime i want to use the PC.. im afraid to shutdown the pc coz the next time i turn it on
this problem is back again.. i've read a lot in asus forum with the same problem but they haven't solve it yet. hope there's an answer with this problem here in your forum.. thanks
and more power..

ps. i've already tried to remove the hardware one by one and start the pc. but it still didn't work.. even with no memory attached the pc don't beep.
i suspect it's the cpu but other says it's the mobo that is problematic.but i really wanna solve this kind of problem with ur help ofcourse.. tnx
(im solving this for almost a month already.. i ask help from different sites but still don't have solution for this problem.)
cpu= amd sempron(tm) 2400+ (1659mhz)
mobo= a7v8x-mx
vcard= geforce2 mx/mx 400
HD= 40gb seagate barracuda 7200rpm, 80gb maxtor 7200rpm
CDrom= cdwriter (lite-on)
dvdrom= dvd reader (LG)
FDD=none
casing= atx tower
PSU=400 watts(tested)
OS= microsoft windows xp (service pack2)
directx version= 9.0c

 

[Maddhatter]

have you tried a new heatsink for the cpu? to me it sounds like overheating

 

[energizerz]

yes.. and it's not about overheating coz even when i run it underclock it's the same... and it runs fine now again.. im using it now with the default clock which is 1.6ghz.. and im afraid to shut down this pc after using coz the next time i use it again i need to do the same procedure for sure.. to start the pc again. remove the paste den start,, then put back.. start.. somethng like that..
check this add of asus=> http://vip.asus.com/forum/topic.aspx?board_id=1&model=A7V8X-MX&SLanguage=en-us
most people there encounter the same problem with mine.
like the no monitor no beeps in page 2 there.

 

[energizerz]

i hope there's somebody who relates..

 

[energizerz]

need new heatsink

after how many days of waiting.. i return the heatsink of my friend which i just borrowed and install my new heatsink with the thermal pad and it works great again. thanks for the idea.