BIOS

The most recent bios update will contain all the information from the previous bios updates. If your system is running well, be sure to save your current bios when updating. If your system is stable and smooth, I wouldn't update the bios. I've flashed a motherboard as many as 3 times in one day. You don't have to wait for updates, or to return to your previous bios version.

Furthermore, i'd like to know if it is possible to download BIOS update in a floppy disk and then update bios through the disk.

I download the new bios and flash program to my documents, unzip them if necessary, and move the unzipped files to a separate floppy. After rebooting with a windows 98 bootdisk, I swap the disks, copy the name of the new file and flash program, and proceed with the bios flash. I've never used the flash programs that run in windows. I think they're less reliable than the old way.

Thanks for your help so far 
Got one more question(sorry for not posting em all together,i just post em when they come to mind!)
Lets say a bios update fix an A problem in a X motherboard.
Is it certain that the A problem will occur when you purchase and use the X motherboard?(in my case there is a bios update that fixes a problem where system cant boot when you use kingston/kingmax ddr400* i haven't started using the mobo yet since i haven't purchased all pieces* is it certain that i will not be able to boot the system if i use a kingston ddr400?)