Recovering data from slave HDD....

Ive recently installed a second Hard drive and mucked around, not knowing how to install the damm thing....so i set the jumpers at the rear of the HD's....one master and the other slave. Anyways ive installed winxp on my new 80 gig HD and set me old 40gig Hd to slave, and when i tryed to read the data on the slave, e.g. open My Computer, click on d:\, it asks me to format.....AND THERES NO WAY IM FORMATING! cause i have so much important information/data on that other HD, so if anyone knows if theres anyway posable way to retrieve that data, ya would be the greatest!!!....and be rewarded
Ive been trying to figure this out for ages, so any help would be absolutly great!
maybe theres some kind of software that can retreive the data??
thanks....