Win 10 boot issue

[Ch3wbacca]

Hey guys, after a bit of help. I recently upgraded mobo and didn't need to reinstall windows as it booted from my 500gb HDD. I shut the pc off and booted it up again the next day, only this time it booted w10 from my 1tb HDD (from my old laptop), is there any way around this? Is there any way of changing this in bios? How I delete the non desired copy of w10? 

 

It may be a simple question to some of you guys, but I'm relatively new to pc building

 

Many thanks!

[VVoltor]

You can go in the BIOS and change the boot priority (or boot sequence) option. 

To enter the BIOS press F2 or DEL during the initial startup screen. (F1, F8, F10, ESC on some systems). The first device in the order list has the first boot priority.

 

To delete windows you could just delete the files and folders on the drive. That might leave a few hidden protected files, a quick format would fix that.

[Ch3wbacca]

Awesome, thank you. I thought it might be something to do with BIOS, thought I'd better ask with me being a noob. Thanks for quick reply!

[Ch3wbacca]

Another problem has arisen. No display with both HDDs connected, so I can't enter bios. Worked fine on my old mobo, win 10 boots alternately from both HDDs. I know it's not a PSU issue as leaving molex in HDD but removing sata boots fine. Can't format either HDD as I have data that I don't want to lose on both. Any ideas? Thanks