If you want to do a Hard Reset but can't do it through the menu, please use the update from T-Mobile UK website: T-Mobile - Help & Support
But use the file from the following piece:
November 2009: T-Mobile Pulse software
This software update should be used ONLY when your T-Mobile Pulse has been security locked and you do not have a valid password.
If you right-click on your mouse here
and select the "Save target as.." option - it should take about 2 minutes to download depending on your internet connection speed.
Installing this update will remove all existing data on your T-Mobile Pulse.
Use the link where it says "here" and download it.
Then in your pc format the SD card. then copy the folder dload to your new formatted SD card. So the folder with the two files will be on there.
Then when your phone is off, do the following:
Vol + key & "hang up button" - keep them both together pushed and then turn on the phone. Then the update will start automatically. Once the update is finished it might hang to long in the "phone will restart automatically". If so, take out the battery again and turn the phone on normally. then it all will go as normal.
Once the update is done, you will have to configure your phone again, which also means you can choose the language again. i have the dutch now.
Hope this information helps. I have tried all others, only this one helped.