My USB is not working well

[Omer1000]

a month ago i bought a USB drive Sandisk Slicer 4Gb it worked great so a week ago i needed to use my USB to install windows 7 there and make it bootable though the USB i did it it worked well also. so now i dont need windows on my USB and i have formted it using right click and format on windows 7 and now he says i have 212 mb and not 4gb

how do i fix this?!?

 

[stefo]

goto START, try right click (My) "Computer" > Manage > Disk Management

find yr flash drive and delete all partitions then reformat

 

[Omer1000]

where is delete or partitions button i cant find