u/Several_Anything_720

Hello me and my friends both have a a dell optiplex 3040 mt and everything was running smooth with them they had theirs months prior (presumably 5) I’ve gotten mine and everything ran smooth for about a week until recently there’s been freezing within five minutes of start up and the day after mine did this my friends pc also started doing this so is this some weird coincidence we did a lot of research and even changed the thermal paste. Does anyone know any other solutions please and thank you?