CFW homebrew freezes all the time after instaling it, please HELP

Hello,

I have PS3 Phat CECHG04 7D console.

It has 40GB hdd, i tested it and it is 100% perfect.

I tried PS3HEN and now i tried CFW.

I did it all by the book, checked nand, used pyps3 checker, used md5 online checker, everything by the book.

And, when I install HEN, i install multiman and start it - IT GOES BLACK SCREEN AND FREEZES.

Same with CFW Cobra, I finish installing CFW, i install multiman and start it - IT GOES BLACK SCREEN AND FREEZES.

Al i can do is unplug ps from electricity...

CFW homebrew freezes all the time after instaling it, please HELP