Depends on what version of BS you are using...
Normally you just reinstall... There are files that 'retain' your configurations and your pending (incomplete) downloads, so no worry, 'normally' !
But, we need more info from you...
Version of BS
Windows version
Memory
CPU
the usual...
Have you recently run any 'Registry Cleaner' or 'Plug-In Cleaner' programs ?
They could have roached some of your settings...
btw, if the BS version is 6, then me know nada... and never will !