Laptop not functioning as well prior to replacing component

[thomashough1]

My laptop is a dell inspiron 15 5447, the issue I'm having is that i've had to gut the thing completely to get to replace the charger connector to the laptop. (plastic holding 4 pins had pinged off) while I did this i also replaced cpu fan. Now, the problems that occured was no.1 I had a black screen up on boot, no screen signal just backlight, checked ram and fixed this issue. Finally got to boot it up, nice welcoming windows update (not) and at first I thought the keyboard/usb components were not connected properly but instead they were. My laptop was just running painfully slow, I would not be able to do any actions what so ever, out of fear that this may be cpu related and the fact I did remove and stick back the heat sink without applying thermal residue. Even so I can't help that think that
these incredibly slow consequences can be caused JUST from the cpu alone? Any thoughts or theories what I may have done/damaged in my laptop would be appreciated. For the record my laptop was working fine prior to this.

 

[ffg7]

check in the bios\setup to see if there is a pc health monitor in there to check the cpu temperature. put new thermal paste after removing old paste as the cpu will throttle it's speed down due to overheating.