It seems unlikely to be related to the BIOS update, since you successfully booted after it, but since nothing else changed, maybe it didn't went down perfect after all.
If you can't get any life signs apart from the power led, and no other idea remains, you might want to try a BIOS recovery.
BIOS recovery usually involves copying the bios firmware file to an USB flash drive, or CD, putting it in, and starting the computer without the battery while pressing down a special key combination on the keyboard.
You should research the exact method for your machine. There goes my extra mile for you
Where would I start? First, finding out what type of BIOS you have. Based on this:
http/forums.mydigitallife.info/threads/7033-Insyde-bios-mod-requests./page513
I gather that your machine have an "Insyde" type bios.
Here there are some instructions for Insyde bios recovery:
http
/forums.mydigitallife.info/threads/7033-Insyde-bios-mod-requests.
Basically you need to know first, what should you rename your bios file to. For shortness sake, it's: "U52F.bin" (See the description below, how did I go for finding it out.)
Now I see only one thing which may vary depending on machine type: the keyboard combination. The description says Windows button + B. Maybe it'll work for you.
Here's the description about finding out the recovery file name.
There's mentioned an "Andy's tool", which can be found here:
http/forums.mydigitallife.info/threads/13194-Tool-to-Insert-Replace-SLIC-in-Phoenix-Insyde-Dell-EFI-BIOSes
There's a long description, all you need is the file which can be downloaded from
http/www.sendspace.com/file/5fub3l
Now, I downloaded this file, extracted, and run the PhoenixTool.exe. A window came up, I browsed for the bios file which I downloaded from ASUS's site for A52F, it's named U52FAS.211 after extraction. Then I pressed the Go button, and after a while, a dialog window popped up, telling me: "Recovery filenames are: U52F.bin".
Good luck!