loss of programs and performance no my pc

this man has deleted some key programs on my computer which are no longer available. he did something to my cd drive where my pc no longer recognises certain programs. after i destinctly told him not to touch certain programs he deleted them. over all he drastically changed my computer to where i can barely use it. i paid him quite a lot of cash and now i will have to put out more to get my pc running correctly. i am extremely upset and dis satisfied with this mans work.