Try this - with the disc inserted in the drive - open COMPUTER - right click on "D" or whatever is your CD/DVD drive - select OPEN from drop down list - from the list of files there should be one with Start,Setup or Application - try clicking on and installing from there.
"I am trying to install tablet software which I used on another PC"
Is it the same operating system that you are trying to install to ?
I am not a Tablet user but are you not able to download the driver software for your Tablet from the relevant website? - or if unsure post details of the tablet and I will try to help further. (or someone else may do)
Can you give me make of Tablet and website you went to. I have to say I that I don't have a lot of experience with Tablets and from the response on here it appears not many others have either - however I am attempting to help you get sorted if possible.