Ok,
I have captured tons of hours of video on celeron/p3/p4 computers. Hopefully, I know a little of what I'm talking about.
Gateway 450 may or may not do this. I assume this is a 450 pentium3... right? If p2, forget it. Ram... 256 may work. I have always used 512 at least. Hard drive... you'll need about 13gig per hour of video captured. This will be doubled when you go to render a dvd disk also, oh yeah, add another 4 gig or so to that total. So, 1 hour equals 13+13+4=30 gigs approx. The pc speed has to be fast enough to capture w/o dropping frames. After that even a slower pc will USUALLY enevtually encode/transcode/burn a disk.
I have always used pinnacle studio 8. If you look around, you can find it bundled with a decent firewire card for about $100 or so (retail). I have a sony handicam with ilink. It plugs right up with no problem. The nice thing about pinnacle is that it captures/edits/encodes/burns. I have had some SERIOUS problems with burning and capturing with different softwares. But, you will need the dvd burning "infrastructure". This typically get loaded if you load the software that comes with the dvd drive.
On a p4 1.8GHz with 512 ram and a good hard drive, expect it to take about 1.5 hours to encode a 1 hour movie. It will then take another hour or so to compile the disk. Then another 30-60 minutes to burn the disk (depending on dvd burner speed).
I have one system: p3 1.2Ghz with 512 ram, 80 gig 7200rpm raid drives, xp pro, 512 ram. It's about 50% slower than the p4. Encoding is very CPU dependant.
The software I had to load to make this work:
dvd burning software that came with my drive (nero)
pinnacle
NOTE: I do NOT use the nero software. It is nero that had problems with pinnacle. Also, windows xp movie maker had capture problems as well.
I did a lot of research and it seems that capturing uses codecs (some type of compression algorithm). These things appear to be copyrighted... so the only way to get a real good one (easily) is to just go buy some software with it in there. If capturing does not yield 13gigs of data per hour, you have done something wrong.
Pinnacle is really nice stuff. Be SURE to download the latest update from their web site. It sped up my render speed and helped with some encoding lockup problems that I had.
Which drive...
When I bought mine, I researched a lot at doom9.org and other similar sites. The toshiba was the hottest thing going then. There is dvd-r(w) and dvd+r(w). I got a -r since the +r was still in first generation teeth-cutting problems. There are some important differences, but I have forgotten what they are (some help I turned out to be eh!).
If you're planning on using a 450 machine, I would go with an internal drive. ANY 450 speed pc will have enough problems writing dvd w/o the added overhead of controlling some external device.
Standard troubleshooting advice applies... turn off any unused processes/etc. You'll need all the ram/cpu cycles you can get.
Have fun!