My Verbatim 4gig store and go usb stick in stuck in RAW Format

RAW format uses enormous file sizes. Smaller memory sticks will be used up with just one single picture when using the RAW format. You're confirmed this when you said it only happens when you use RAW format. You need to use a larger memory stick, if you want to use the RAW format.

at the command prompt (dos) type chkdsk x:/f /r (where x is the micro sd)

Try to get a software called parted magic. its linux based and you should easily format the pen drive.
U can also try HP USB Disk Format Tool.

virus in your pendrive.
so format your pendrive dos command

start than run than type cmd than enter

ok and command type is

format (your pendrive colon) enter

i sure your pendrive format.

1. Download this tool:
http://dl.dropbox.com/u/4040651/LLFTOOL.EXE

2. Format

(WARNING: After running this low level format tool,
the whole USB flash disk surface will be fully erased.
Therefore, data restoration will be impossible after using this utility!)

My usb was suddenly says used capacity 0 bytes,free 0 bytes,FILE SYSTEM raw.Cannot be formated.it says insert flash drive.give me the best solution

Hi
Just go to My Computer.right click on Manage.Then click on Disk Management.In the bottom tab you can see your pendrive.click on it get a new partiotion using NTFS.

Try this --

Download the HP disc format tool using this link--
http://www.eocfiles.com/bdc86eb1ed2989c30dcd1902e84939ae/bootdisks/SP27608.exe

After downloading the file you need to install this. 
After installation,launch the software, and select the Flash Drive Letter and try formatting.
If this does'nt work,plz let me know and I'll give you one more alternative.

1). Do not format this hard drive before you've recovered all your stored data back. In your case, the formatting process may erase everything on your drive and make your data gone permanently.
2). Never save anything new on this drive in case that any new file would rewrite your original data.
3). Plunge this drive to your computer and download a RAW drive data recovery freeware to get back all your lost data back:
http://www.freeware-fix.blogspot.com/2013/02/raw-hard-drive-recovery.html
This hard drive has helped many people around me restore their inaccessible data back from a RAW drive or memory card. It can also work perfectly on your drive.
Read more detailed information of this freeware here:
http://blog4mark.blogspot.com/2012/10/help-external-drive-became-raw.html
4). Save and back up all your restored data on another drive in case of data recovery failure.
5). Format this drive to see whether it is fixable.