computer problem

I almost tired of my laptop slow performance. I already tried everything i can do to make it better like cleaning up the disk, defragment and even scan the virus but seems like those are not the problem. Husband says i got too many junk downloaded in the system and i should have to delete some of them but i can't since those files i have are important. I don't know if transferring my file in usb flash drive is helpful. I guess i have to try it though. And oh, i need a new wire for charger so bad. We been looking at it in the store for past few weeks and they ran out of stocks. Don't know what to do when my computer is not working properly. It drive me crazy.