Windows 7 Black Screen with movable cursor after loggin to windows7

[Nitrox]

Hi everyone, I am having some issues with windows 7 it started about a couple or days... The day before yesterday I was cheking some videos at youtube, all going as usual (fine) then I shut the cpu down , got to sleep and turn it on the next day and after loggin into windows7 a black screen appeared with the cursor, that i could move. ctrl+alt+del did not worked, esc or enter, nothing. So I rebooted manually and nothing happens. After that I run safe mode, a full antivirus scan and malware, all clean. So I restart in normal mode and It worked fine yesterday, but today the issue appeared and I did the same as yesterday but now is not working, I have been looking answers for this in forums , some of them says that is maybe a malfunction from a driver of nvidia, or a windows update , I changed the wires from monitor aswell but still not working , this problem is driving me nuts

System spec: Intel Core 2 Duo 57500@2,93ghz, 2 x Kingstone HyperX 2gb 1066 ddr2, Nvidia 9800 GT 1 gb ddr3. OS Windows 7 Home Premium.

Thanks !