Some Practical Advice
My Advice: Buy DVD versions for those movies in your VHS library that are now available on DVD, especially if they are films you like to watch on a regular basis. Since DVD has much better video and audio quality than VHS, as well as most DVDs having supplementary features (such as commentaries, deleted scenes, interviews, etc...), and with the price of DVD movies being fairly inexpensive (especially if they have been out for awhile), this would be a better solution in terms of time.
Keep in mind that it takes two hours to copy a two hour movie, as the recording is done in real time using a DVD recorder, whether copying from a VHS tape or DVD. For example; it would take 100 hours to copy 50 movies (if you are actually able to do so) and money (you still have to get 50 blank DVDs) spent on trying to make copies of old VHS movies onto DVD.
For those VHS movies that are not currently on DVD or may not be anytime soon, you can try using a Macrovision Killer, which is a box that is placed between a VCR and DVD recorder (or VCR and VCR).
However, in the case of DVD Recorder/VCR combo, you need to check if the VCR section has its own set of outputs and if the DVD recorder section has its own set of inputs and that if the VCR can play at the same time the DVD recorder is recording, independent of the internal VHS-to-DVD dubbing function.
You would then connect the Macrovision Killer to the outputs of the VCR section and the inputs of the DVD recorder section. In other words, it would be like using the Combo as if it were a separate VCR and DVD Recorder. Your user manual should explain how to use your DVD Recorder/VCR combo in this fashion (minus the Macrovision Killer part) and offer an illustration.
Using a Macrovision Killer between a VCR or DVD Player and a DVD recorder, or between the VCR section and the DVD recorder section of a DVD recorder/VCR combo, may result in successful copy. However, this method may not work in all cases. Also, such devices are getting harder to find as a result of legal crackdowns.
The Legality of Copying Commercial VHS tapes and DVDs
As part of a recent U.S. Supreme Court ruling, even companies that make hardware and software products that can bypass anti-copy codes on DVDs or other video and audio content can now be sued; even if such products have disclaimers regarding the use of such products for illegal video or audio copying.
Several companies that make products that enable DVD-to-DVD, DVD-to-VHS, and/or VHS-to-DVD copying are on the target list to be sued by the Motion Picture Association of America (MPAA) and Macrovision for making products that can be used for copyright infringement. The key to the ability of these products to bypass anti-copy codes is their ability to detect them.
Copy-Protection and Recording Cable/Satellite Programming
Just as you can't make copies of most commercial DVDs and VHS tapes, new types of copy-protection are being implemented by Cable/Satellite Program providers.
One problem newer DVD recorders and DVD Recorder/VHS combo units have is that they are unable record programs from HBO or other premium channels, and definitely not Pay-Per-View or On-Demand programming, due to copy-protection to block recording onto DVD.
This isn't the fault of the DVD recorder; it is the enforcement of copy-protection schemes required by the movie studios and other content providers, which is also backed up by legal court rulings.
It is a "Catch 22". You have the right to record, but the content owners and providers also have the legal right to protect copyrighted content from being recorded. As a result, the ability to make a recording may be prevented.
There is no way around this unless you use a DVD Recorder that can record on a DVD-RW disc in VR Mode or a DVD-RAM format disc that is CPRM compatible (look on the package). However, keep in mind that DVD-RW VR Mode or DVD-RAM recorded discs are not playable on most DVD players (just Panasonic and few others - refer to user manuals).
On the other hand, Cable/Satellite DVRs and TIVO do allow recordings of most content (except for pay-per-view and on-demand programming). However, since the recordings are made on a hard drive instead of a disc, they are not permanently saved (unless you have an extremely large hard drive). This is acceptable to movie studios and other content providers as further copies of the hard drive recording cannot be made.
Also, if you have a DVD recorder/Hard Drive combination, you should be able to record your program onto the Hard Drive of the DVD Recorder/Hard Drive Combo, but if copy-protection is implemented within the program, you will be prevented from making a copy of your hard drive recording to DVD.
This is also one of the reasons that standalone Blu-ray Disc recorders are not available in the U.S. - although they are plentiful in Japan. The manufacturers don't want to hassle the recording restrictions imposed in the North American market.
I doubt if anyone is going to knock on your door and arrest you for making a backup copy of a DVD if you are able to (as long as you don't sell it or give it to someone else). However, availability of devices that enable you to make DVD copies are in increasingly short supply as the MPAA, Macrovision, and their allies successfully win lawsuits against companies making software and hardware that enable the bypassing of anti-copy codes on DVDs, VHS tapes, and other programming sources.
The era of widespread recording of copyrighted content onto DVD, may be slowly coming to end as content providers prevent their programs from being recorded.
For an additional technical explanation and perspective on the issues revolving around video recording and copy-protection, also read the article: Understanding Copy Protection (About.com DVRs).
For complete information on what DVD recorders can and cannot do, check out my DVD Recorder FAQs