BIOS Upgrade taking way too long.

I just recently figured out that the BIOS couldn't even detect all the RAM that came with my Inspiron 4150. Instead of detecting 512 MB total RAM in my chips, it would only detect 256 MB, or whichever card was in slot 1. I tried making a BIOS upgrade so it can support the RAM and HDD fully (80 GB only showing up as around 14 GB.) However, when I restart the computer to perform the BIOS update from A04 to A06, it takes so long, or it just doesn't work. The hard drive LED stops working, but the screen doesn't freeze, and the little "_" keeps flashing. I tried leaving the computer like that for about two and a half hours, only to see no signs of progress. I checked to see if the hard drive still worked, and could hear a faint spinning sound from the Seagate. I actually turned off the system, but although most people will say that it won't boot, it still booted normally, and loaded Windows XP like normal. I don't know what went on, but it sure seemed like no upgrade even happened.