Max Min Close button disappeared in KDE

I was experimenting with Slackware Plasma 5(3.9 GB one), by Alien Bob, using sbopkg I installed qupzilla web browser, but it took 5 hours to install , in that period around 100 other applications were installed by them selves with most of them being or something to do with qt! after a restart, the min max button on the applications and web browsers etc disappeared, and could not resize by edge dragging, is there any way to restore the Plasma 5 to default state?

Likely the KWM window manager crashed, so you get windows without decorations. You can restart KWM manually, but I don't remember the details off the top of my head. Some googling should get you going now that have an idea of what this confusing problem actually is!

kwin-x11 had crashed and has to be reinstalled, but it is on the DVD, when I get time I will do it, meanwhile thank you for the reply!