windows registry, restore?

my laptop was okay, i tied to install my nokia phone 3500c, it said cannot install this hardware, data is invalid, did net search for usb cannot install, what i did was stupid, i opened windows registry went to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet, right clicked on permission and selected allow all (although some of the options were on "read", then my phone worked fine as usb drvice, but when i start windows restore, it says windows restore cannot protect ur computer , please restart, i did, it did not work, my printer driver also vanished, can i undo changes to the registry, my laptop was perfectly fine, i just tried to take things in to my own hands and i’m in a mess ,even the linking between excel documents is not working since please help

Hi there, I’m currently experiencing a frustrating problem when accessing the Nokia Music Store.

I’m using the Nokia Music Store for Singapore and it requires me to download the Nokia Music software in order to proceed. After downloading and installing it, it states that I am unable to access the store and have to check my internet connectivity.

However, when I enter the website through my web browser which opens up the Nokia Music software, I am able to access a particular page in the Nokia Music Store which I have attempted to click on using the web browser. About 5 minutes later, the Nokia Music program will crash and I try to re-open it. Unfortunately, trying to open it, I get this message:

"There was a problem starting Nokia Music. Running the Repair option for Nokia Music in the Add or Remove Programs section of Windows Control Panel may resolve this problem." Hence, I try to repair the software using the abovementioned method, but I still get the error when attempting to open the software after repairing.

This has thus prevented me from accessing the Nokia Music Store through all possible means. And I am therefore unable to enjoy the privileges of the 1-year Comes With Music subscription since it is registered to my computer.

Please help me in this problem, all help is greatly appreciated. 🙂

Thank you very much.

hi i am suffering this problem from one week actaully i am installing nokia pc suite n when it goes to 80% the error appear like this
could not open the key:
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID…
and i tried lot of registry repair softwares like TuneUp Utilities 2007,Registry Mechanic,easy cleaner etc but no solution and i also apply the microsoft method and some others methods which are in the following links
http://support.microsoft.com/kb/912996/en-us
http://www.aspdeveloper.net/Virtual_Server_2005/rn-738-10822_1402_error_on_install.aspx
http://forums.ni.com/ni/board/message?board.id=170&message.id=148774

and i asked from one computer expert he said there is no solution for this problem only reinstall windows but i cant do that coz i have lot of important softwares and important data in my drive c: plz plz give me a 100% working solution for this problem i will very thankful to you
waitin….