Dell — Fully Reprogramming my laptop

Dear sir,
Good Morning. i purchase my dell laptop at al ain centre LUCKY STAR COMPUTERS in dubai.i use near 4months i uae, after that i get vacation 2months gone india.
When came back to uae i forget to take my dell acceriess support cd and laptop bill.
Past one month i had problem this laptop sometimes its was hang and some programe missing and i cannot able to use webcam.its requeried resoures cd and system was slow.
I want rectify my problem but i don't have cd and bill. its still under warenty preoid. i was purchase in july or augest 2010. i want re programe Fully hardware and software like before when i purchase.
Can you able to slove my problem.

my laptop details ----- Dell, Inspiron-1564, intel core i5, windows-7 Home Premium,
Service tag # DH8Z7M1.

Please your help is needful on this matter.
Thanking You,
Yours sincery,
k.mohammed fazulullah, [protected],
swehian, near abu dhabi.