You don't say whether you already have the two computers networked and sharing Folders and Printer(s). If not, in the PC, go into the Network and Sharing Centre and make sure the network is set as a "Home Network". Then click the link at the left for "Change advanced sharing settings" and switch "On"...
- Network Discovery
- File & Printer Sharing
- Public Folder Sharing
Repeat this in the Netbook.
In the PC's "Computer" (My Computer), highlight and then right click your DVD drive, select "Share with > Advanced Sharing". In the Properties sheet that opens, click the Advanced Sharing button. In the next window, tick the box to "Share this folder" and then click the Permissions button. I'd suggest that you add your own name to the Users list and ideally you want to be logged on to both PC and Netbook with the same Username/Password.
In the Netbook's "Network" (My Network Places), you should then have access to the PC's DVD drive.