Sounds like a profile corruption. Without looking at it, I can't know for sure, but here's what I suggest you do.
First, I want to know if you have antivirus software installed on your computer. Things like this can be caused by viruses. It doesn't happen like this a lot but I can't rule it out just yet. If you don't have antivirus software, download AVG or Avast! for free here
Next, if you can, I want you to create a new user account for yourself. You may want to copy these instructions down somewhere, since you'll have to be logging on and off a couple times.[Note: When performing these steps, make the new user account an administrator account when presented with the option.]
Here are the instructions for Windows 8: http://www.bleepingcomputer.com/tutoria ... windows-8/
Here are the instructions for Windows 7: http://www.bleepingcomputer.com/tutoria ... s-vista-7/
If you have files on your desktop in your old user account, you should copy them somewhere safe so they don't accidentally get deleted somewhere along the line. I recommend making a new folder in the C drive with your name on it.
Next, using the new administrator account you just created, locate C:\Users\(Username) and find the NTUSER.DAT, .INI. and .POL files. They may be hidden; if they are, tap the Alt key, and click Tools > Folder Options. In the View tab, select the bullet for "Show hidden files, folders and drives" and uncheck "Hide extensions for known file types" and "Hide protected operating system files."
Delete the NTUSER files I listed above and log back in to your account. Let me know if the problems are fixed.