How to remove Windows icon on boot

try both pram and smc resets (google)

if that 4th partition still works, check disk utility to make sure that there are no stranded partitions

if nothing, then i'm not sure how to get rid of it beyond doing a clean install of both OSs

Whatever you did last time didn't work - don't try that again!

Back up everything before you begin.

Bootcamp Assistant (in Applications/Utilities) will remove Windows partitions, however I expect in this state it will remove the Windows 7 partition. It may resolve the issue, but it will delete all the Windows data. Perhaps Bootcamp Assistant does something extra compared to deleting the partition by hand?

If it still has the multiple boot icons you will have to erase the HD completely and then restore your OS and user data.

Do you really want to erase & start over for this minor issue?

so I decided to erase it, found a tutorial and did it with Disk Utility,

By removing the partition using Disk Utility you made the initial error. After that you can't correct it without following Drew's advice. Erase the disk and reinstall from scratch. But I might be tempted just to ignore it (unless there are more issues).

Where did you find a tutorial advising you to use Disk utility?

from your screenshot, you don't have stranded partitions

you can try drew's step first, use bca to delete windows, but i think you're still going to have the ghost windows remain

if you really need to get rid of it, then yes you would clean install osx then windows, the mistake will be fixed