Originally Posted by JeremyBoden
If it was Windows, it will wipe all other pre-existing OS's off your disk.
If you want dual boot, put Windows on first, resize your disk, then install Debian etc...
I got the impression the OP loaded Debian on to of Windows rather than the reverse. ("over ride my window" [sic] = "overwrite Windows")
BTW Don't load a server version of Debian if you want a desktop version.
I've been using Debian for a long time and I've never heard of a "server version" and this link
confirms its non-existence.