Do you mean OEM disk? And what exactly is it you need this disk for, we'd be happy to help you find a solution here but we need more information about your goals.

there was no operating disc with the pc, a dell optiplex gx240,is it possible to make a bootable disk, i know the windows number

if my pc goes down i will need a rebootable disc, thanks

You'd need to legally aquire the windows disk to do it that way, what I'd suggest is using Clonezilla or to create an image of the system that you can use to restore down the road. Or you can borrow a disk from somebody when you need it.

Also, some OEMs will sell you the original restore disks for your particular system for cheap, you can try contacting Dell to see if that's an option.

thanks, i`ll give that a try, i`ve also sent an email to the seller asking for a copy.

I suppose it's worth mentioning that some modern systems have "restore partitions" instead of rescue CDs. I don't know if that's the case but it may be worth looking into.