Can I update BIOS with a USB if I don't have floppy drive??  

Read the bottom of this page, see if that will be what you need:

Flash Bios From USB

Just in general terms it can be done. Specifically, not for every MB/BIOS. A Guy

Welcome To Seven Forums. It looks like you have an Abit? If you would please take the time to fill in your system specs.
Top of page>user CP scroll down left hand side edit system specs and fill them in it will help a lot.
If you have a cd drive you can also flash the bios from thier. Here is a tutorial using Nero 6 How to create a botable Bios iso image file How To Create a Bootable BIOS ISO Image File. If we can get your exact model # we can check and see how abit suggest to go about flashing your bios, it is something you don't want to do wrong or your system will definetly be buggered. Thanks. Fabe

Ok, here you go.

1) You have an ABIT IP-95 motherboard with an AMI bios M618ZF10 which is the old 2006 bios. Go to this page:

Universal abit > Motherboard, Digital Speakers, iDome, AirPace, Multimedia

Download the file called M618ZF13.zip which is the latest bios for your mobo. Save it to the desktop.

2) Unpack the zip using any free unzipping software like 7z or winrar trial version. It unpacks into a folder containing five files. These include the .bin file which is the actual bios file, AFU408P which is the actual flash utility and Runme.bat which contains instruction on flashing.

3) Copy all the 5 files to the root of the bootable usb flash drive you have ready. Then boot from the flash drive. At the command prompt, type:

runme

Then hit Enter.

4) The page at link on 1) has additional info on what to do after the flash.

Switch off the power supply unit or pull off the power cord. There is a CCMOS jumper near the battery . Change the jumper position from default 1-2 to 2-3 for one minute to discharge the CMOS data, and then put it back to default 1-2. Switch on the power supply unit or pull in the power cord. Press the power-on button to boot up system. If it works, hit " Del " key to enter the BIOS setup page to do correct settings.

Bill2 said:

1) Best to flash windows using an external device like CD, floppy or USB flash drive, rather than from within windows. Flashing with a flash drive is a breeze. You need to make a bootable one using a tool like the HP format utility. This tutorial will walk you through.

MS-DOS Bootable Flash Drive - Create

2) The usb flash drive should be set as the first boot device in the bios.

3) Copy the files for your bios to the bootable flash drive (after downloading from the manufacturer's website and extracting the individual files from the zip or exe).

4) Then boot from the flash drive. You'll get a command prompt like A:\> (as shown in the picture). Then type the command for your SPECIFIC bios EXACTLY as required and hit Enter. If you goof here, theres a good chance, the mobo will get bricked.

5) If you provide more info about your system specs and bios, as Eric advised, we'll be able to help you more.

number 1) is no longer true and the majority of bios upgrades i perform for myself and customers have been done within windows.

number 4) is an example where using an external device can go wrong ?

the majority of problems I have seen with bios flashes in the last 5 years has been user error and this is increased when using external devices with very specific command lines ?

your advice here is very sound but I wonder if your first statement still rings true using todays motherboards and bios ?