If the problem is that some NV memory is resetting the password after the CMOS is cleared, I'm not sure how flashing the BIOS would help. Looking at lordevil's suggestion
The issue is greater than that. The problem is the laptop has some NV memory and eeprom. If you reset the bios, it auto-reloads from the NV memory.
I'm not sure the specifics of this NV memory (as well I don't have one of these laptops or the like), but the trick would be to prevent this from re-loading the CMOS settings stored there, forcing the password out of that.
One could change the BIOS if the EEPROM is socketable, by unpluging the BIOS chip, and either flashing it in another board, a BIOS flash utility (I think they had one of these in some of the hardware engineering classrooms we have down at the colleges I'm attending), or by swaping in another BIOS chip. However, the problem is CMOS memory itself, which when wiped, from his suggestion is getting restored from this other memory.
Though it could be possible to change out the BIOS, if one can remove the BIOS chip, I'm not sure this would help remove the auto-refresh being suggested from CMOS memory itself. It might still refresh it?
Convenient would be if the stinken NV memory spoken of were on the same chip and it were socketable. Then simply ordering a new chip and plugging it in would fix that.
I did look some, and saw references to the same instructions on shorting pins 3 and 6 next to the CMOS battery, when I did a little searching on this. The downside, are suggestions about having to "rip the laptop apart". Personally I'd want to know a bit more before
And though I've rebuilt PCs and the like, umm, well laptops, hmm...
Ideal would be if Dell support would be willing to throw a tip your way, even though you might not have bought it from an authorized reseller I'm gathering.