From the FAQ on the National Geographic site
Not sure which version you have so I pasted the one's I thought might work for you. It took me about 2 days to figure how to do this.
Installing TOPO! data on your hard drive (TOPO! State Series)
1. First, insert the CD-ROM you would like to copy onto your hard drive (with the exception of disc 1) into your CD-ROM drive.
2. View the contents of the CD-ROM using Windows Explorer. Locate the folder called XX_DOX (XX is the two letter state abbreviation), right click on this folder, and choose "Copy" (for example, CO_DO7 for Colorado disc 7).
3. Now select the C drive, locate the TOPO! folder, then locate the sub-folder called TPO_DATA. Click on this folder, then right click in the pane on the right and choose "Paste".
4. Repeat this process for each CD_ROM you would like to copy on the hard drive.
Installing TOPO! data on your hard drive (TOPO! Regional Series)
1. First, insert the CD-ROM you would like to copy onto your hard drive (with the exception of disc 1) into your CD-ROM drive.
2. View the contents of the CD-ROM using Windows Explorer.
3. Open the folder called XXX_DATA. (XXX is the first three letters of the location name - for example, YOS_DATA for TOPO! Yosemite).
4. Highlight and copy ALL of the folders located inside the XXX_DATA folder. (To highlight more than one folder at a time, hold down the Control key and click on each folder you would like to highlight).
5. Once you have highlighted all of the folders, right click on one of them and select "copy"
6. Next, locate and open the TOPO! folder on the C drive.
7. Inside the TOPO! folder, locate the sub-folder called TPO_DATA. Right click on this folder, then select "paste".
8. Repeat this process for each CD_ROM you would like to copy on the hard drive.
Installing TOPO! data on your hard drive (TrailSmart National Park Maps)
1. First, insert the CD-ROM you would like to copy onto your hard drive into the CD-ROM drive.
2. View the contents of the CD-ROM using Windows Explorer. There will be a number of folders titled XXX_DATA each representing a National Park.
3. Open the folder called XXX_DATA (XXX are three letters that relate to the location name - for example, YOS_DATA for Yosemite).
4. Inside the XXX_DATA folder, you will find approximately seven sub-folders (number may vary by park). Copy all of these folders (to copy, highlight all of the folders, right click on any of the highlighted folders, then select "Copy" from the menu).
5. Now locate and select the TPO_DATA folder on your hard drive. Paste all of the sub-folders into the TPO_DATA folder (to paste, right click, then choose "Paste").
6. Repeat this process for each National Park you would like to copy on the hard drive. Once you have saved all of the data to your hard drive, TOPO! will no longer ask you for the disks.