SL won't start up - a REAL stumper!

I sent a special questions ticket to Linden Labs and they never got back to me (yes, I have a premium account). I asked computer-savy programmer relatives and they're stumped. This is the only place left to turn! There has GOT to be a solution to this problem!

I recently got a whole new computer set up. SL worked fine at first, although it gave a few signs of over-heating (things would occationaly stretch and go weird). After a while it started freezing up. any sound would get stuck and after a second or two both my screens would go black, with the sound still stuck. Then both screens turned back on and everything was running normally again and I'd get a little error box that told me something was wrong with the graphics card and it had to be restarted. This happened about three times, then on the fourth the screens went black and didn't come back on, the sound still stuck. So, I forced it to turn off and turn it back on. Everything seem'd normal, though there might have been some problems the first time on startup, I can't remember... Then when everything did start up normal SL wont start up. It gets as far as the program opening for a split second - the black before the log-in screen - then it closes down and the SL crash-register thing pops up to file a crash report.

My operating system is Windows XP
My Graphics card is an ATI Radeon HD 2600 XT

it sounds like it's something to do with the graphics card. So far, I've un installed and re-installed both the program itself and my graphics drivers. I've updated the drivers, un installed SL, deleted all remaining files, re-installed, even tried beta and other SL clients - all produce the same effect.
I'm not incredibly computer savy, but ANY suggestions would be greatly appreciated!

Not sure if the followings will be of any help but please try them:

- Are you able to watch any VCD/DVD or play other games without blackout?
- Open the PC's casing, check if the graphic card's fan is spinning. If not, then card or/and fan could be damaged.
- Check the Catalyst Control Center for the temperature of your graphic card.
- Unsit the graphic card and resit it back (when PC is off)

No good! other high graphics games work like a dream. It doesn't even have a fan (just a heat sink) and I already tried taking it out and whatnot.

This is a KNOWN problem! Many ATI "Directx 10" cards have Second Life issues. I have also submitted a Service request and I ask ANYONE with this issue to do the same TODAY.

This isn't a 'fuzzy line' or 'off color' issue......it just DOESN'T WORK!! If LL isn't made aware of this, we all will sit in front of black screens until THEY press ATI to solve it.

OH! problem solved! I can't BELIEVE this....

I switched my primary monitor.
This caused a 3 month absence! I think I might cry.

this problem seems to be solved by setting your color depth to 32bit in windows...that's all i did and it's working fine now