WHICH SYSTEM CAN SOLVE ANY KIND OF COMPUTER PROBLEM( SOFT)?

there is no really definite answer it will really depend upon the damage in ur computer. if its only a case of a simple virus u can install an anti virus but if its really a bad one and had affected ur computer entirely u might need to reinstall ur operating system.

But if its only an issue of speed. suddenly it went slow maybe ur directory is full of junk slowing ur speed u can istall directory cleaners (CC Cleaner). also check back ground services if u have useless ones.