XP doesn't want to boot and cannot afford loosing my documents. so my question is .....
Does the Repair Install from the XP setup partition page delete my documents and other installed programs?
As manojgj has said, the XP Repair option on a genuine Windows XP CD won't harm your data but you used the word Partition. If that's a part of the hard disk the manufacturer set aside for a Recovery, it will take your system back to the way it was when it left the factory.