no boot? and artefacts

[agonyoftechnology]

Problem:
PC seemingly will not boot. Graphic Glitch (artefacts)
Software:
I use a Dual-Boot (ubuntu 15? and win7)
Hardware:
AMD 6300 FX (overclocked quite a bit, but ran fine)
AMD RADEON 280 by ASUS (or sth. that sounds like it)
4GB Ram
2x SSD
1x HDD

Description:
When I press the ON button, the PC makes a “beep” noise, Fans and Hard drive spin, all seems fine so far.
But the Monitor (Panasonic TV, connected via DVI-I) shows only artefacts.
A Few times, the PC would boot by default into the linux partition. Once loaded I could use the PC normally without any graphical glitch.
This does not happen any more (my guess is, it PC will now not boot at all).
When I tried to switch to the WIN7 partition (blindly) the PC did not boot, or at least, did not stop to show artefacts on the Monitor.

Any Ideas how I might solve this issue?

 

[pointerboy]

Hello.

You must've messed up the GRUB boot. I'll focus on no boot problem because I'm not affiliated with the GPU(s).

Since, the computer started and booted Linux we can remove the hardware option. Try downloading Windows 7 Installation disc (Change boot from option to CD/USB or whatever you have Windows 7 disc on) then go to repair my computer > Command Console > And type in following commands:

bootrec /fixmbr
bootrec /fixboot

That way, you'll get Windows 7 boot first and you can select Linux dsitrs from the boot menu.
Good luck!