This is what inevitably happens to every computer running the Microsoft Windows family of operating systems. Once your computer has been running for a while, the registry and filesystem gets so full of useless junk from old programs and bloatware, that it slows the whole system down. After you've defragged a million times and cleaned up everything imaginable, you still can't get your computer back to the way it was when you first installed Windows. The only cure is to reinstall a fresh copy of the operating system. That will keep you going for at least another 3 months.
Man, my system is so winrotted, I can't do a damn thing with it.
My computer has winrot so bad, even Doom won't run on it!
v., win·rot·ted, win·rot·ting.
1. The inevitable creeping, pernicious degradation of the integrity of Windows systems to the point where they run slowly, behave erratically, or stop working altogether.
1. To cause Windows to decompose or decay. “Adobe Reader winrotted my fresh install”.
1. The process of Windows rotting or the condition of being rotten: “The winrot spread quickly, rendering the system slow and unstable”.
2. Any of several Windows programs characterized by the breakdown of stability, speed or security. “Don't install Norton. It is absolute winrot”.
My nephew only used my computer for 10 minutes, but once he was done the winrot was so bad I had to reinstall Windows.