Moongamers, Thank you!
Problem fixed!
Special thanks to all of you that helped me out;
Monkey T_C, thank you for putting your heart into this, you have been a real good allied in this search, I will always remind this.
Gremlin_FLG, good idea for the PSU, might be useful for me to remember / learn about power supplies... (and Welcome, I missed your first post!)
Leeham, your idea of the socket being not working properly / not being the right one was the final step that brought back my computer to it's peek, Thank you!
Pest_Control, thanks for being fast on the reply like you have been, and for the jumper Idea, it was good, I know on older system jumpers could change alot, good thing to remember.
Katmandu, Thank you for your propositions, I'll keep in mind the battery trick, might be helpful in the future and
I will not forget you just because you PM'd me instead of replying here And from now, I will keep an eye on this forum, it's amazing what the help of friends can do, I'll try paying back this help by helping with my own humble knowledge of computers.
On a final note, I'll be more cautious in the future if I'm to upgrade something, i'll question myself before I do as to "is the thing satisfying my needs, or am I just upgrading to see what will be next?"..
Personal thought: Upgrading Reminds me of playing Black Jack, when you have a hand of 16, the dealer might be 18, and you hit just to see if you can beat / even him with a 2...