What you are proposing to do is in effect digtising all your video and audio media
No mean task.....
While Im sure software like Roxio 8 could help to automate some of these steps ( esp audio) a few basics are required
You will need to get your video footage from camcorder or VHS to the PC with something
like this
There is a Pinnacle product Studio 10 with hardware
this which is similar but more featured then the first one.
These will allow you get the video to the HDD and convert them to mpeg4. Studio will probably get you to buy an add on pack : If you have the divx. xvid codecs on your PC you may not need to buy these.
There are freeware, shareware , paid for ( and P2P : Im not endorsing that

) utilities which can help convert your captured video to mp4
Some TV cards can do the same job but will require you to open the PC up as they mainly tend to be PCI cards
With video 8 in particular, there may be some Sony Digital8™ camcorders with DV output ( digital to PC) which can play video 8 and convert them in-camera to digital for transfer to the PC.
Some of these camcorders have a feature called pass thru which can also enable you connect a VCR to it on one end and out to PC on the other. I must say they are getting scarce but just worth mentioning. If your video8 tapes are really valuable you could record them to DV tape with a miniDV camcorder with
analogue in then later transfer them to PC as you would a "normal" digital tape
There is a small freeware program called Audacity : with it and the appopriate cable connected to your PCs sound cards (line in) from the audio cassete players output , you can get the music from your audio cassetes to the PC as wave file or even mp3
I would recommend doing that with Roxio 7.5 or 8s' built-in dedicated music program : "Audio Central" I think its called
There are probably others but over the years Ive converted cassette tapes to audio cd with relative ease with earlier versions ( It was called "Easy cd creator" then)
What you propose, though possible has a more than a few learning steps, needs learning a few programs and knowing something about audio and video file formats and how to convert them
I would suggest bite sized projects till you get the hang of things
I suspect it will take a good few posts to cover the whole thing properly

Phew.....
Good luck