After updating BIOS, Windows 7 won't start up !?

No need to panic. If it is less than a year old, it is under hardware warranty as well as full tech support. They must replace it if they can't get it fixed. And since they pushed through the Update they will most definitely do so. You should not be monkeying with it any further without great experience nor should we be pressing you to do so.

A BIOS update is not a run of the mill update and as stated should not have been pushed through in this way. I would have had them on the phone assisting the process in case of failure so they would be witness to it and expedite RMA Repair or REplacement. Do this now. They really have no choice for putting you out on a limb like this. Tell them we are watching.

Its barely a week old ! I bought it on September 19th 2011.
I've contacted ASUS, still awaiting their '48 hours' response, and if they fail to provide me with a fix or if I don't manage to somehow figure out the solution, I'll press them hard with complaints. I have pick up & return 2 years warranty !

In hope to find a quick fix, I found a YouTube video of someone showcasing their BIOS, it looks very similar to mine, although the laptop model is different and a bit older I think - G73Jh. But what caught my attention, I've noticed SATA Configuration line in Advanced Settings - I can't recall seeing that line in my BIOS, but I'll recheck - if I find IDE/AHCI/RAID settings there and do the switch - it might just be the solution & the quick fix I am looking for. Fingers crossed, I'll report back if I manage to find this ..

Found it, finally.. but suprisingly what I've been looking for all this time made no difference whatsoever !

BIOS / ADVANCED / SATA CONFIGURATION /
SATA Mode Selection : AHCI / IDE

I changed from AHCI to IDE, which I expected will most likely load the Windows after startup (in case the Windows & its drivers were set up to work with IDE in the previous BIOS version). Suprisingly! it made no difference whatsoever. Weird !

Thats it. I tried everything I guess. I'll see what ASUS says and act upon it. It always leaves me with the final least desirable option to boot up from the disk & reinstall everything all over again, hoping that it will work out.

@p5bdkw

Yes I know that, but this whole story was about restoring my Windows 7 to load normally, as it was before the BIOS update. If I go with reinstallation as the final solution, I'll boot from Window disc..

BTW. Does Windows 7 Installation disc have any option to load/recover the already installed Windows, or I'll have to format the previous stuff and do the full install again ?

Thanks, I'll boot the Windows disc and see how it goes, hopefully it will offer me the same recovery window as explained in the link.. I have OEM though, not sure if recovery will be included.

tough luck once again !
after booting up the disc & choosing repair computer..
Message: System Recovery Options
This version of System Recovery Options is not compatible with the version of Windows you are trying to repair. Try using a recovery disc that is compatible with this version of Windows.

Agh ! I'm tired of it all, I'll reinstall everything, whatever happens it can hardly get any worse !

Many hours later.. I've finally restored my system back. It took complete reinstall of Windows plus all drivers. At the end I was 'lucky' that reinstall process went ahead properly & also that Microsoft accepted my Windows 7 reactivation.

One of the first things I did, after reinstalling Windows & drivers with ASUS drivers & software disc.. I've promptly uninstalled the ASUS BIOS Flash Utility (Windows Version).. WinFlash I think in the control panel. That thing is a damn time ticking bomb waiting to kill the system ! Its my advice for anyone who has this installed to remove it straight away. Having such application, that flashes BIOS directly in Windows and backed by the ASUS Live Update - anyone forgetting to uncheck BIOS ver. update among the rest of other updates can easily have their system doomed by 1 unintentional click. And even worse, cancelling during the process - You'd be completely system crashed & left without BIOS..

This whole after-BIOS-update-no-Windows issue remains unanswered & unresolved.. If the same thing would have happened with a working laptop with data on it - everything would be lost !!! At least my system was brand new so I "didn't loose anything". At the end of the day I feared the worst, now I am just grateful to still have the laptop & Windows I can work with.

Wow...

I'm really glad you were able to reinstall and reactivate Windows, but yeah, that BIOS update mess sucks and I hope either Dell or Asus gives you an answer. We're all wondering just what the hell happened...I still wonder if Windows is running with IDE or AHCI drivers right now (not that it makes any difference now).

But glad you're back in business.