Windows 7: Diagnostic Policy Service Not running! Help!

Ok so i was attempting to replace my keyboard on my dell studio 1749 windows 7 home premium x64 laptop. I took out the battery, unscrewed the screws to take off the main cover where the keyboard is. Could not get the cover off so pushed it in where it has kinda of snapped off, turned on computer and went to go look online for how to get it off. Started up computer saying dell dock could not run, and my internet wasnt even turning on at all, i couldnt connect. I troubleshooted it and found diagnostic policy service was not running. I went to turn it to automatic and restarted and all that, when i tried to start if from the thing it said error code 5 access is denied. My system restore wasnt working from before this so that isnt an option, and the laptop did not come with a windows seven clean install disk even though i bought it direct from dell...
help would be so appreciated i could cry