I can't edit neither modify my Registry..

[facnode]

Hello i'm using windozs xpee as OS..i used some power tweaks to enhance my security wid da help of windows patch comes wid Digit Magazine.....But now i found that i can't modify neither can edit my registry.
I wanted to remove some items from my startup..i tried using Msconfig.exe but can't apply the changes...even i logged in as administrator rights...all in vain..

can anyone suggest me what to do...?

Regards

Facnode