|Personally I wouldn't use a computer that has no access to the internet these days. |
There is no built in software codec in Windows of any version that can decode encrypted DVDs, which is what pre-recorded ("factory") DVDs for movies or videos are.
You must install a DVD player program that has a built in software codec that can decode DVDs, such as Power DVD.
Once you have installed at least once such program, you can also play DVDs in Windows Media Player, at least you can in newer versions of WMP.
If you have an (XP) MCE 20xx version, you can then also play DVDs in Media Center.
E.g. CDs or DVDs that come with retail desktop mboards, or the free CD or DVD that often comes with a "bulk" desktop optical drive, often has a free version of Power DVD or some other DVD player program that has the necessary software codec.
OR - Buy Power DVD or some other DVD player program that has the necessary software codec at a local place that has software for computers - it has more features when it's a "paid" version. .