Dell Inspiron 1525 not starting after cleaning heat sink

Good Morning All,

I have an issue with my Dell Inspiron 1525. It was over heating but it had no startup problem. The computer works well and I am able to use every application.

But after cleaning the heat sink, The computer do not start, Please help me if I need to do any other checks.

Here is what I did to clean the heat sink. I removed the heat sink, removed all the dust and placed back again, I also applied Thermal greese as well. But when I tried to start the laptop, all the multimedia inidcators above the keyboard (mute, volume increase, volume decrease) are seen working as usual, I can hear, it trying to use the DVD drive, I can hear the fan working. I can also see the power indicator (only) in the left corner of the laptop. No hard disk or wifi indicators. I also do not see any of the three error indicators (next to the power button above the keyboard) shown.

One thing to note is, when I tried to remove the sink, the processor also came out. So I loosened he screw, fixed the processor..

I did not completely disasseble to laptop, To remove the heat sink I just touched the eight screws under the laptop and five screws of the heat sink.

Please advice if I need to do any other checks.