Seems like they r starting up with windows.
you should understard a little bit of DOS to do this.....
download startup manager.
install it(virus free hehhe)
Restart your PC.
While your PC is restarting (Just before it shows the loading screen) press F8 key and go to startup screen.
From their select safe mode with command promt support.
when windows loads, it'll show you your user names select administrator account( or select your own account if you have full administrative powers).
Now at the comand prompt go to the folder where you installed startup manager.
Type dir and see the folder tree.
from their start the startup manager's executable.
go to the startup manager's main page.
delete every startup entery except explorer.exe and userint.exe.
type shutdown -r -t 01 and press enter.
your pc will restart.
after restart run a fully updated Anti virus a fully updated anti spyware maleware and fully updated anti trajune software...
you should get a clean and fresh PC with out reinstalling the windows agian n agian.....
i'll be here.