Yes he did say he overclocked to 600/1200 and iirc temp he mentioned was also way above the roof.
I think you should try cleaning the RAM modules, removing them and then re-inserting them. I know RAM has no relation with graphics card but I had this very same bug once and replacing the RAM solved my problem (I had blue and yellow vertical lines however).
oh really? i should try with RAM thing now. i will remove all three modules and keep 1 module which is cleaned. wat i did is, i removed nvidia drivers, then i logged in safe mode ran driver cleaner, and then my card was showing me same lines in boot up screens and desktop and welcome screens were clean. and then when i installed drivers. again i got those patterns 
and making this card worthless. while playing games yesterday i didnt overclock it was just 500mhz core and 900mhz memory. cause i know of summer the temp might go up. max temp went up was 85deg during most wanted benchmark. but i was playing prince of persia the two thrones. now what am i supposed to do? i lost the most imp asset of my life cant live without it.
shall i try formatting xp again?
If your getting the Lines from the BIOS itself , its not an XP Problem.
Did you remvoe the card, and clean the Pins?
i removed card and cleaned all the pins… they r proper… 
i also cleaned the card thoroughly replaced heatsink compound on HSI bridge and on GPU. i see the edge or HSI bridge on the edge little broken 
can anyone help me
Post a clear pic of the affected part …
i cant. dont have a digicam just have a webcam. i can show it on webcam gpu also has 1 side of edge chipped off and also HSI Bridge chip is chipped off. but it works gives display without drivers. the prob starts after i install drivers and get patterns in bios screens and xp load screens. and display goes off at welcome screen and then after removing drivers from safe mode, i can use my pc. weird proble
no help? depressed.. feels like suicide
its a common problem in 6600GTs … coz the HSF is not properly fitted and u can bent it in both directions … so it will damage the GPU core … mine 6600GT is also have some edges broken but its working fine …
can u try the card in some other computer … or some other card in ur computer ??
What do u mean u can bend the HSF in both directions? :S Btw u have a 6600 GT also?
^^ yeah the HSF is fixed only in 2 points … rather than all 4 points … lemme explain with a pic … here is a pic of my 6600GT (can’t find any better than this) …
http://img162.imageshack.us/img162/2836/6600gtproblem6zm.jpg
in the pic u can see the HS can be bent in the direction of the arrow and it can damage the core … same is true for HSI bridge but as the HS is small its not that bad …
i also read somewhere on the net that to be careful when handling these cards …
yeah i have a 6600GT in my secondry system …
I understood that the heatsink is fixed only at 2 points. But under what situation would it bend in that direction?
but my geforce 4 works fine! but i also cant load drivers on my Geforce4 :o same problem like Geforce 6 card…
looks like your cards are fine…but your mobo isnt!!..:no:
hey i could load drivers.
but overnight my Geforce 4 is getting more worst patterns then my 6600GT wat seems to b the prob here? is it the AGP slot:O
can anyone help checking my Geforce 4 and Geforce6 cards whether they r working fine or not i dont have any friends or relative which has AGP slots. can anyone from mumbai help me. pls
Geforce 4 is also toast? i get even bad patterns on my Geforce4 card.. why such things happening to me!
OT but i lost 2 512MB RAM modules on the same day yesterday…life surely sucks