If you have lots of money, you can by basic parts and see if that fixes the issue. Also, cloning the partition and OS from any source does not guarantee genuine copies of the OS as it may not completely give you your files, incorrectly copy your files, or give you a bootleg that doesn't boot. Also, as a previous comment said, removing the HDD may solve the problem as it could be corrupted, damaged, improperly configured / placed, and so on. also, from what your saying, it seems like you get to the login screen, it just goes blank. You might want to run an antivirus / registry / disk cleaner program(s) to see if your computer has bad files. Also, if you suspect the problem is the two GPU's and graphics card(s). Then you might want to take them out to see if your computer runs with the bare bones.