If you can get it to stay on for long enough, try using the disk cleanup tool to clean up your hard drive. Defragging could also speed it up also. By shut down do you mean it just goes black and nothing works anymore or do you get a blue screen? You can try booting into the recovery console and running chkdsk to try and fix any hard drives issues if they exist. The command for that within command prompt is chkdsk c: /r
That command could change if your primary partition is another volume.
They be like bob, what?