Computer boots but screen flickers.

JoeliPowder

Honorable
Dec 15, 2013
19
0
10,510
It boots but the screen flickers and on some of the flickering screens there is a flashing underscore in the top left hand corner. It goes past the BIOS and the screen flickers for a few seconds. After that, it shows the BIOS screen again for a moment. I feel like it keeps booting and rebooting.
The problem may be that I was installing a new cooler and some thermal paste got on my motherboard. The paste fell on a little black square with little silver connectors to the side. Paste also fell on other parts of the motherboard like into the PCIe 3.0 slot. Is that causing the problems?