Do you mean it sits at the Windows splash screen for a long time, or it takes a long time before it even gets past the BIOS screen? How old is it? You can try defragmenting your drive or running some cleanup tools like CCleaner and other things. Old machines usually get junked up over the years with software that is installed and uninstalled. I typically just save my data off and reinstall the whole thing. You can also check to see if you are overutilizing your RAM and it is using the hard drive to swap memory. Your Task Manager can show you how much RAM you are using.