Hi have you tried another monitor to see if you have the same blinks, I have a 620 with no problems, it could be the monitor, hope this helps,   Terry

This is'nt the monitor because I took mine to a friends computer and it worked perfect.

I really have no idea about it...

Something to try for a temporary workaround:

 

Right click on desktop

Choose properties

Choose settings

Choose advanced

Choose troubleshooting

 

There is a hardware acceleration slider that you can try moving to the left. You can try different settings with that to see if there is some point at which your hardware will work. If there is some setting there that will allow the computer to work, maybe that will give someone else a clue to help you get it fixed properly.

 

Also, next to the troubleshooting tab is a monitor tab. Click that and see that the box for "hide modes this monitor cannot display" is checked and then see that your frequency choice is one of the ones showing after the box is checked.

 

Regards.

bc