Would appreciate it if someone can point out what I can do. I have a dell inspiron 600m which is 5 years old and still serving me faithfully. I use ubuntu on it and have a cpu temp monitor app. Now I usually open it to dust out the fan vents but never touched the sync. Today I found the sync completely clogged and so I unscrewed ( making sure not to touch the part which lies just over the cpu so as to do nothing to any thermal paste but as far as I could tell , no paste was left) the sink and then blew the clogging dirt and stuff out and put it back on top of the cpu. I screwed it back and now my laptop feels less hot and more responsive but there is a problem. the cpu temperature monitor app is now jumping around. I mean it goes straight to 66 from 57 and back to to 58 and then 52 and this is weird so now the question. How much should I have tightened the heat sink screws ( which lie on the part lying above the cpu) . Have I tightened it too much ? Too little or sth else. Since I did not do anything to the thermal paste( also by looking there was none) so I believe there is something wrong I did while reseating the sink. Please help.