motherboard connectors

Hello, i will keep it short. I changed thermo paste cleaned dust put everything back like i always do. I turned computer on - fan spinning power light on but hdd led blinked once and display was off. I removed ram and hdd few times changed ram slots volia somehow everything worked again what a...

I get a bit jittery when I'm unplugging cable connectors (these images are just examples, I'm thinking of all types of connectors). What's the best way to safely unplug them?, pull from the cables or from the plastic case. What's your experience? http://i.imgur.com/lUllecb.jpg...