No picture in iMac after SSD installation

I have just installed a 1TB Samsung 850Pro SSD in my iMac. After replacing the standard 1TB HD(OWC procedure) I booted up the system in safe mode and formatted the SSD in one partition of 1TB. After that I restored from a Time Machine copy the latest backup. Everything went smoothly until the moment it needs to reboot. After a while forced a power off reboot. It rebooted but up to the moment that it needs to show the desktop. There is no desktop visible.
Tried a Time Machine copy from another drive and the same happened. No desktop. What on earth is going wrong? I own a mid 2010 i5 iMAC with a 1TB HD originally devided in 2 partitions, one for OS X and one Bootcamp/Win7. The latter I am planning to restore after OSX by means of Winclone.
Hope somebody has the solution to get this sorted:

What I did was replacing the standard HD with a Samsung 850Pro SSD 1TB.
After that I started up the system with a USB which I prepared before on the same system with a clean Yosemite 10.10.3. This will got me into a mode which gave me the option to use the disc utility, start up from the Yosemite USB or restore a Time Machine copy. I first used the disc utility to format the SSD into one partition. Then I choose to restore the last Time Machine copy which I made a couple of hours before. The Time Machine copy was on a USB disc connected to the MAC. Everything goes smoothly up to the moment that the system needs to restart. I waited 15 mins but nothing happened, it did not restart so I forced it to restart. The boom came, the Apple appeared, the bar appeared and after it filled up for about a third the screens goes black whereas it should show the standard desktop. I have done this twice from two independent Time Machine copies, both with the same result. Then I disconnected the Time Machine USB disk and tried to install a clean Yosemite copy from the other USB stiick with the Yosemite copy. Same result. Black screens. I have done this procedure 3 times already on a MacBook and it worked perfectly so what is going on here. I appreciated you help very much.

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One more thing: Yes, I ran the test facility in the disc utility and it says all OK. I can start up with the alt key pressed and I can make a choice from which disc to start. If I choose the standard disc it eventually results in the same thing, black screen. I did not test any other modes because i.m.h.o. they don't make sense when the OS is not starting at all.

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At the moment I have reinstalled the standard HD disk and the system runs smoothly again. So the hardware should be OK, right? Timing issue, setting here or there I have no clue??

In the mean time I have found out that it probably is something more of a software problem than a hardware problem. I have tried to put back a Time Machine copy which I made an hour before changing the HD. I have never had any problems with restoring an Apple iMac from the Time Machine copy except now. Everything seems to work/start up but the screen stays black after the Yosemite bar disappears. After doing this a couple of times I decided to restore from an older Time Machine copy. This worked, the iMac started up but the only thing I could not restore is the Outlook database which I don't like because it means that I have lost all my email. Have tried all start up options but no dice, nothing worked so far. Anybody have any idea...it must be a software bug or something in Time Machine??

Problem solved. It appeared to be a software problem in Yosemite caused by Apple and not solved by Apple. Thanks Apple. In the end solved with the help of a bunch of enthusiastic Apple fanatics. Thanks guys!