Is my flash memory dead?

I have a Verbatim Store n Go 8 Gb flash memory since a few months. I've been using it to test win 7 beta lately. Today I used my win 7 beta DVD to uninstall Win 7 ( I had dual-boot XP and seven) with the program bootsect.exe in "boot" folder from my DVD (command: "E:\boot\bootsect.exe /nt52 ALL /force" where E was my DVD drive) and I had the flash memory in my USB (not using it, I just left it there) The uninstall went fine, my XP boot sector is ok, but now I see that my flash memory is not working!!! On any PC the same symptom: When I plug it in, it says device installed and ready to use, but when I double click Removable Disk (F: ) in my computer I get: "please insert disk into drive F:" I tried formatting, nothing. Even in "computer Management>disk management it is displayed as "disk 1 removable drive - no media" In xp and vista and seven its the same. I tried Linux Partition editor (ubuntu 8.10) and it would not even see it, only in computer where are all my HDD are displayed could I see "USB disk" but it would not mount. I tried diskpart in vista, I selected disk 1 and when i tried the clean command I got error "there is no media in the device".

I don't know what else to try, sorry for such a long post, but I wanted to explain everything,

thanks and I hope somebody will help me.