As Robert states in his title, nope, don't even dream of reinstalling without the CD. That said, two thoughts come to mind. First, that's outrageous that the repair shop would take the original install CD and not return it with the repaired system (The fact is they shouldn't really need the CD itself, just the valid key code, for which it would be a reasonable business practice for them to insist on seeing the certificate of authenticity with their own eyes before proceding, but they don't need to keep it.) Can you go back to the shop and put a little pressure on the manager to make this right for you?
Second, one of the little secrets of Windows install disks is that within the major product lines (Pro vs. Home) the contents of the disk are all the same. The installation routine will ask you for your product key, shown on the inside of the package folder and/or typed on a label which is stuck to the back of your computer somewhere. The key is unique for each copy, and will ultimately be registered with Microsoft as being installed on that specific computer. Subsequent reinstallations on that computer will be immediately recognized by Microsoft as a valid license, but using that key on any other system will fail (or conversely, using a different key on that system will cause some trouble too). That's why the repair shop needed to know the proper key. But in your current predicament - if you can read the label on the back of your system to get the product key AND you can borrow a copy of an installation CD (of the same version as yours) from a friend, you can perform the reinstall.