Hi Stephanie and welcome to GTG.
Does this occur in Safe Mode also? If not, read the link below in my signature and get those programs. If you have Windows XP, either try downloading them in Safe Mode with Networking or get it from another computer and burn them on a CD.
For the desktop/wallpaper problem:Do you also have the wallpaper problem? If you do, do this also:
Right click on http://www.greyknigh...pairDesktop.reg and download that file. Double click on it and click on Yes when it asks you if you want to merge it into the registry. Once that's done, restart your computer.
Login as usual and now right click on your Desktop and go to Properties. Next go to Desktop tab->Customize Desktop button->Web tab. Uncheck everything listed there. Then delete all the entries listed except for 'My Current Home Page'. Click OK and OK.
Make sure to get us the HijackThis log.