Computer only loads and black and blue and missing login screen after changing PSUs and clearing CMOS

[Bast]

Hey guys, have a problem my friend could use help with.

His power supply failed yesterday, so I gave him my old, but working, one to replace it with. Once he installed it he said the fans and machine would turn on and sound functional but no display would appear on the screen. Also, there weren't any beeps when he started it up because his computer doesn't have an internal speaker that more modern ones come with for diagnostic purposes.

After it wouldn't display he reset the CMOS to see if that would help, and it didn't.

Then he realized he hadn't plugged in the PSU to CPU cable on the motherboard (derp) and had only plugged the 20-24 pin one in.

After he plugged it in, the system would start and display. However, it only displays in the colors blue and black. For example, when windows is booting and the starting windows logo comes up, it's not green yellow blue red, etc. it's just variations of blue and black.

Finally, once windows does load, it's just a blue and black screen with a cursor and no place to login to a user or anything. Just blank.

I'm thinking powering up his rig without the CPU cable plugged in but everything else plugged in, clearing the CMOS, powering up again, and then realizing the CPU wasn't powered and fixing it and powering up again did something wacky to make his GPU only load blue and black. I have no ideas about the missing login screen though. The only other step he has tried so far is reseating the RAM, but it didn't do anything.

Any ideas on the next step to solve either problem?

 

[itzdanielp]

Can you double check that the vga cable is fully plugged in and there are no missing / bent pins? Make sure it is fully plugged in on both sides of the monitor.

Also, double check that the GPU is full seated in the slot, and that if there are any aux GPU power cables necessary that they are plugged in as well.

 

[Bast]

Thanks for the quick reply, let's try it and I'll repost. Keep any other suggestions coming though!

 

[Bast]

All checked, still same results. However, there's a development. After miscolored windows starts and it goes to the screen like it's about to pull up the login screen (you can even see the background flowers and things that are on the default desktop, despite that they have no color except just shades of blue), a prompt comes up asking if he wants to install Windows 7...

At least we know why the login screen isn't coming up, but did his hard drive get wiped? Weird how it says starting Windows and then asks if he wants to install it when you can see the desktop background and everything.

Is it even possible for Windows to have been wiped? Any more suggestions for the discoloration?