I just upgraded to WM5 for my SX66. Everything went fine until I actually fired it up, the program is Stalling. I tap start and it takes it about 15-20 seconds to ever drop down. The active sync will only work about once then say it is disconnected. I can not use the thing. It will not recognize the SIM. I had The WM2003 SE before and it ran like a top. I AM AN IDIOT! Can anyone help? Can I reinstall the WM2003? How and where. Oh God, this is terriable!

If you have a backup of your data (or are willing to lose it), have you tried doing a hard reset?

I did that and restored from a backup & it worked great on my former 'brick'.