Regd: Background jobs!!!!

Hi Experts!

I 've some background jobs(develop sys) which are schedule every day in SD ,

but unfortunately time has set as around in the afternoon,

BUt that jobs Interrupting Some transactions,

My basis guy has suspended the background jobs,

but when i check sm37 , the jobs still working,

But what i need is ,to delete all jobs which are scheduled ..permanently

and want to reset that jobs

and

how do i set that SAP System time to our local time??

Can any one pls suggest me ..

Thanks

Srujan