Long time linux user here, need some windows advice.

A bit of context:

I've been running an airgapped W7 sandbox on a separate partition for a bit of light gaming, mostly older singleplayer titles and the like, i'd download the title to my storage drive whilst booted into linux, then turn off my router and boot into W7 to install it and play, as such i never worried about malware because it can't really do shit and i'm savvy enough to detect ransomware lighting up my cpu and pull the plug before its done encrypting, plus i have backups so whatever.

Recently i've been thinking of going back to an mmo that i played a few years ago and that's going to require network access, so what i'm wondering is how do i scan the shit out of that W7 partition so it becomes safe to network?

I don't mean like malwarebytes and shit, but hardcore deep rootkit / MBR scanners, software like roguekiller if that's still a thing, or better, i haven't used (like actually used) windows for years and i'm a bit out of the loop, so to put it as simply as i can: what would windows-wizards do to Asian/Slav-proof a windows installation so its safe enough for gayming and casual low-risk browsing?

>pic unrelated