Something to check out.
Navigate to C:\ProgramData\Microsoft\Windows\Start Menu
Check the Security settings under the Application directory. Mine is shown below. The only one in mine that has full control is Administrators of HomeI (my computer name) computer. but you can add or grant permissions as you wish. For instance "Everyone" could have full control or your user name also. Attachment 227157
I have added a couple of links one to a tutorial on customizing the start menu from this forum and a link
to the how to geek. If you read through these and check out your start menu as you read you may find your problem. Since my start menu is ok, I can't point you to the exact cause. Start Menu - Customize Tweak the Start Menu in Windows 7 and Vista - How-To Geek
Post back, If you can't find the menus I am refering to we will give some more info.