Hey mate,
Its probably an AMD processor (not MD) and these are good gear, but if its 6 years old then its likely that this is pre 9000 series (not sure exactly when they came out but think they are more recent than 6 years)
So old processor, but probably still worthwhile. The fact that it has quad core is slightly redundant unless you are running 64bit architecture and programs as mostly they wont be able to use it.
The RAM is good at 4Gb, the graphics card is a decent ATI Radeon, but think at this age it only came with 256Mb Ram on board. Thats not alot for todays applications.
The 15" monitor is tiny!! You would definately be wanting to upgrade that at some point, but a decent 22" will cost under £100 these days so not a big expense there.
The BIG thing to look for though and the thing that most PC manufacturers bluff and keep low so they can sell "bargains" on tele is the CACHE. You want a minimum of 2Mb these days and the more you can afford, the better. It really makes a HUGE difference.
...Sorry, long winded answer to say I think £200 is at the top end of the scale for this.
Would I recommend it? Hmmm, for a wee computer to surf the net, type a few messages in oOple (

) and do a bit of Microsoft Office then its going to be ok. But if you are looking for a computer to do you for the next year or two, look elsewhere.
Mesh (my recommendation), Dell and HP (sometimes) make decent entry level computers for between 300 - 400.
Hoep that helps.
Sorry for the length of reply!
Cardnim <-- nerd / geek