There is an excellent reason why it is possible to buy a cheap Dell 420: no one in their right mind would pay good money for it.
The most apparent flaw in its design is that it was built to run the Windows OS, but the fact that this virus-riddled, illogical, overly-complicated, and deeply annoying operating system exists is hardly Dells fault and it is perfectly possible to run the Linux OS on the D420, which would remarkably improve it.
The bigger problem is that it looks like a businessmans laptop. That is, effectively, the D420s only viable customer. While Dell insist that it has inherited the wonderful aesthetics of its predecessor – the D410 what exactly is so special about plain black plastic with silvery plastic trimmings remains to be seen. The D420 makes looking boring and nondescript into an art form.
In fairness, though, how a computer looks has little impact on how it performs. The D420 has all the bells and whistles you would expect of a high-performance laptop, but only a 60GB internal hard drive. Given how big the Windows OS alone is, that leaves very little space for music, games, software, pictures, and all of the clutter of a young persons lifestyle.