The blur is due to whatever device you’re using Windows 10 on and its set DPI scaling option, the problem does not have anything to do with Windows 10 itself and you would encounter the same on any Windows version.
In fact, beginning with Windows 10 Creators Update (Version 1703), a new setting has been added for this, “System (Enhanced)”, which you’ll find under the Compatibility tab of the Properties for any executable. This new enhanced setting can vastly improve most DPI scaling problems, but unfortunately won’t do much for Messenger 7.x, other than making the text in the menubar (if shown) crisp again.
sadly it is windows 10 because my main coputer has 10 and i use it almost daily. of course it is not so nostalgic but i have a couple of xp macines which i can run messenger on.
POLLS ARE IN. it seems that Windows 7 comes in as the top ranking, Windows 10 as the 2nd, and Windows XP Professional as the 3rd, when I made this, I thought Windows 10 was gonna win, but time proves me wrong…