To see your permissions, right click the folder/file, click on properties, and check out the security tab. Check to see what permissions you have by clicking on your username (or user group). Here are the types of permissions you can have: http://windows.microsoft.com/en-US/windows-vista/What-are-permissions. You need to be an administrator or the owner to change permissions (and sometimes being an administrator or even an owner isn't enough - there are ways to block even them from access (though a smart administrator knows these ways and can get around them - but usually shouldn't because they were denied access usually for a very good reason). Here's how to change folder permissions in Vista: http://www.online-tech-tips.com/windows-vista/set-file-folder-permissions-vista/.
To fix this problem with the folders, take ownership of the folders or the drive (as an administrator) and give yourself full rights. Right click the folder/drive, click on properties, go to the security tab and click on Advanced and then click on the Owner tab. Click edit and then click the name of the person you want to give ownership to (you may need to add it if it isn't there - or it may be yourself). If you want it to apply to sub-folders and files within that folder/drive, then check the box for replace owner on sub-containers and objects and click OK. Back out and now there's a new owner for the folders/drive and files who can change permissions as needed. You can now change them from read-only (even if the main folder says they still are read only - you can have access yourself as the owner). You can keep them as read-only for other users and guests and even administrators (though they can take ownership themselves and gain access if they so desire and there really isn't much you can do to stop this except protect the folder with a password using a 3rd party product. Here's more information on taking ownership of a file or folder: http://www.vistax64.com/tutorials/67717-take-ownership-file.html.
Good luck and I hope this helps!
P/S. I hope you know what you're doing because if these are the real system folders you'll have to do a clean install to repair the problem it will cause.
Lorien - One - MCSE/MCSA/Network+/A+