Hardware

some pen drives have a tiny switch on them that enables or disables write protection.

Then some software has been removed and you need to go to the Makers Web Site and download their software.

Col

When you say that you changed the registry key, you're sure that you changed the WriteProtect DWORD value to 0? If that didn't resolve the issue, have you tried booting your pc in safe mode with command prompt and formatting the drive? If you haven't, steps to perform that are as follows (per Tom's Hardware):

1. Shutdown your computer or laptop
2. Insert USB Memory Stick into your laptop or Computer
3. Turn on laptop and then immediately start pressing (F key then Advanced Boot Options screen will come up
4. Select Safe Mode with Command Prompt
5. After loading files if your USB Memory Stick drive letter is (G) for example then write as
6. C:\windows\system32>G: and press enter
7. G>format G: and press enter
8. If ask you (Y/N) then press (Y) and press enter
9. Now a full format will start which remove write protection from USB Memory Stick.

Command prompt formatting source: http://www.tomshardware.com/forum/277331-32-disable-write-protection-drive

Registry key editing sources (& steps): http://www.troublefixers.com/remove-write-protection-on-usb-pen-drive-or-memory-card-or-ipod/

http://maketecheasier.com/windows-qas-remove-write-protection-from-usb-drive-setup-parental-control-blurry-screen-after-update-and-many-more-week-12/2012/04/25

I had a similar problem with one of my drives (an IMation drive in my case) which refused all normal means of writing or formatting. I even tried several Partition Volume manager programs to format. No go.

The final workaround for me was to run one (or two, do not remember now) of my Flash drive speed and validation test tools - but to run them in the Write Test mode. Which generates an expected warning, like, "*Danger [Will Robinson], Write testing will delete all data and volume information and will require a reformat!*" (or something similar to that message. Be SURE to have the correct drive letter selected!)

After the destructive write testing, which showed the drive was either 100%OK or was 99% OK (again, I forget detail result) I was able to plug it in and the standard Windows Drive tools Format utility was able to format it as a FAT drive and make it useable.

The two Flash drive tools I used were:
Check Flash v1.16, at http://mikelab.kiev.ua/index_en.php?page=PROGRAMS/chkflsh_en (a free program).
and
HDTune 2.5.5 Free version, at http://www.hdtune.com/download.html .

Hope this helps.

My flash drive is same with yours, (bruceprem)
with the same problem.
I also tried everything to remove the write protection.
I've been reading a lot of solutions and many are recommending to just have a replacement. I just bought it a week ago. Can't afford yet to buy a new one.
Still seeking for its recovery.

and I took it to another computer and it worked so I safely removed it and took it back to my computer and did not have the problem again. Before trying it on another computer I must have tried it on mine at least 3 or 4 times. Why did this fix the problem, I don't know. Nor do I know if the problem will happen again.