Help, Full - Write Protected USB

[darkjoe16]

hey guys, i need help, i have SanDisk CruzerSlice 8gb USB Flashdisk, and i already used it for 2.5 years wihout problem at all, but suddenly when i need to format it, it said "The Disk Is Write Protected", i tried to find solution on web, like adding some registry "DevicePolicyStorage" and erasing or modified the key "WriteProtect", then using some software like Any Drive Formatter, and format it in Safe Mode, but in the end , the result was zero, and still bothering me, i'm affraid this is a virus or something, oh and i tried it format it on other computer on different OS, the question is is my USB Falshdisk can be fixed or the timelife of my USB is Over and i should buy new one? Thanks!