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Hmm... well I know my Windows 98SE, 500mhz, with 256mb ram can't run high definition, but it handles just about everything else with a bit of tweaking around(this includes most games that I am interested in as well). Just about any anime I have ever watched is easily playable(including from the DVD, when my DVD player decides to work) except those in .mkv format. OGM runs fine usually; though after playing them so long(about 45mins to 1 hour) it starts to choke on me.
As for High Definition I have ran into problems with my current rig on some of them(1.8 Ghz Intel Celeron, 2GB of ram, 512mb ATI Radeon); which is sad to me.
However, I will concur that 300$ is a bit much for such a machine. I would likely pay 100$; maybe 200$ tops depending on stuff like how good is the battery, the size of the Hard-drive, and what extras are with it(such as useful pre-installed software, drives, does it have a station[I assume it is an ancient machine if it is that slow, and they usually have docking station capabilities], etc).
Just for a comparison I'll list two recent examples:
-We payed around 300-400$ dollars(don't recall exact amount) for my desktop; used of course. 1.8 Ghz Intel Celeron, 2GB of ram, 512mb ATI Radeon(I think, it might be a 256 though I have it recored as a 512 from when I checked out each part individually), 2x 200 GB hard-drives, 2x Ultra Speed DVD/CD Burner Combo Drives, and it even had a fancy Viper case with it that it all went in.
-We sold a 1Ghz, 512mb ram, 40Gb Hard-drive desktop computer[onboard video and sound, just a standard CD-rom Drive; mainly cause our spare DVD/CD-rom Combo burn Drive didn't work with the spare motherboard... we were going to charge 100$ with the addition of it) with WinXP on it for about 75$.
Things to keep in mind, laptops are more expensive in general than desktops(even used); in addition a good working battery can be worth a decent amount.
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