Yes,

P4 1.5GHz
128Mb RAM
40Gb HDD

That box almost certainly shipped with Win ME. To take it to XP without a memory upgrade is not a good idea. I would have upgraded it to Windows 2000 (NT5) OK, no good if you want to play old DOS games, but neither is XP. If you really want to run DOS Apps, go back to Win98SE and dual boot Win2000 or a linux distro?

I would not like to run XP with less than 384Mb. I don't know his local prices Konshuss, but over here you would go to Crucial and get some more RAM............much better value than changing the OS?

The problem might be that it is RAMBUS RDRAM.............now that is not cheap!............like Dell tried to charge me just under £1,000 for a Gig of it! He should be able to get it second hand/used though............I since got 512Mb for £84 (a slight difference ) You have to fit them in matched pairs as well I would guess there are plenty of 128Mb strips around?

just a thought