Problem being Faced after creating the DELL Diagnostic Bootable USB Flash drive .......

Hello Everyone,

I have a DELL inspiron 530 Desktop and my OS is Windows Vista ............ I made a bootable USB flashdrive (using JetFlash V30 4GB Pendrive (TS4GJFV30) )to run DELL Diagnostics Version A1340A0 ........ while doing so a message was popped up as follow :-

"The selected flash drive is too large for a single FAT 16 partition. Only a portion of the drive will be usable after it is formatted by this Utility. The full capacity of the drive can be restored later by reformatting with another utility."

so then i continued with the process and made the bootable flash drive ......... after this i rebooted my computer and performed the DELL diagnostics and then booted into the Operating system i.e. Windows Vista and formatted my Pendrive ...........

but then while i checked the pendrive capacity under the properties section it showed just 1.96GB while on the contrary it is a 4GB pendrive ..........

so now i wanna restore my pendrive to its original FULL capacity of 4GB by reformatting my pendrive with another utility  .......... i searched a lot for such a utlity but was unsuccessful ...................

so now i want help from your side as to which utility to use in such a case in order to reformat my pendrive and restore the full capacity of it  ...........

any help would be greatly appreciated ...........

thnxx in advance ................