Is there a COA sticker on the bottom of the laptop or under the battery with a readable Product Key?
This is your ticket to Clean Reinstall - Factory OEM Windows 7
as often as you want for the life of the PC.
This is a much better install without all of the Dell Factory bloatware and useless duplicate utilities which have much better versions built into Windows 7, although if you still have the factory preinstall you should be able to run Dell Windows 7 PC Restore
There may also still be a bootable diagnostics partition so try running that now to check the status of your hardware: Dell Diagnostics Utility - How to Run the.
If it runs then be sure to leave that partition intact if you Clean Reinstall, deleting all other partitions during booted reinstall.