ok guys thanks for your suggestions,I am getting this PSU changed ASAP(this weekend most prolly).
This is what happened yesterday(cudn't post yesterday cos my net sucks.Life in general sucks).
Since I can't just sit and see my 8600gt lying around on my table,I tried it for the last time,This time recording every observation in minute details like a true scientist.
I tried my default PSU(I won't tell its wattage,you guys will laugh.This is a Zenith OEM PSU),ANd tried booting with G.card,no display but it was booting up from XP+vista+ubuntu discs normally(I can see from the drive's blinking LED).I then tried with the new PSU,same thing as above.I restarted several times waiting for some miracle,ANd yea it did happen,It booted with the g.card!.I installed drivers,and restarted.It did boot up again normally.(I didn't even touch this set-up to make sure nothing escapes my eyes).I installed Soldiers of fortune,and played it a bit.Then I installed gears of war(Bugger took about an hour to install and took up 10gb space).The played it a bit to make sure card is working fine.Then I restarted it several time without touching anything except the on\off keys of UPS.Then I tried changing the dvi cable's ends to make sure it's ok,It worked like a charm(DVI>>>VGA,it so much more clear).Then I thought its all fine and now the PSU should be put in its' position.but voila as soon as I fixed the PSU in its place in Cabby(I am 100% sure I din't touch g.card or power connectors or anything).It hasn't booted up on g.card since then.It happened just after I positioned PSU on its position in cabby.
pretty long story,eh?lol.SO what do you guys think now?I am sure g.card is working all right.I checked using gpu-z some other tools.I think its either my Mobo or the psu.But the mobo works fine on onboard video.Is it that that PSU delivers sufficient power sometimes and sometimes not?Or that its got some loose connections?Problem is I got only about 2k rupees so I can either get a better PSU(after returing this one) or add some more to get a new low end c2d mobo.
And yea It does boot up everytime,its just that display doesn't get any signal,maybe the g.card doesn't get enough power i guess.
This is all so confusing.dammit.
so what do you guys say now?