Booting Problems With Dell Optiplex gx270 and gx260

I have both Dell optiplex gx270 and gx260 desktops which I bought at reduced prices from the company where I work.

Both PCs had no OS installed on them. The gx270 had a 40GB hard disk but no RAM. The gx260 had no hard disk but had a 256MB RAM (PC2700 type). According to my IT folks at the workplace, those were the only issues with the machines as they 'scrapped. them to me.

The gx260 initially had no power supply but I later obtained one from a working Dell PC and installed it.

I took out the RAM on the gx260 and installed it on the gx270 to ensure that the PC had both RAM and hard disk. I then tried to install windows XP. When I switch on the system, the 'hard disk' indicator light comes on and the indicators for the 'Scroll Lock' and 'Caps Lock' on the keyboard come on alright but NOTHING showed on the monitor when I try to boot it up.The screen was blank.

I installed the same RAM and Hard disk on the gx260 but I experienced the same problem. Nothing showed up on the monitor.

I tested the monitor with a working PC (Pentium II) and found it to be working OK.

The working PC had windows XP installed on it. I replaced its hard disk with the one I was using trying on the gx260 and gx270. The PC boots alright and starts to run windows 2000 but at a point a screen bearing the word SNOW appears. SNOW is a speciliased software used by my company for PCs on their networks.

Is it a case that the DEll optiplex gx260 and gx270 have some problems? Even without the hard disk, nothing shows up on the screen when I try to boot them.

Could the hard disk itself be faulty, please? Or is the 'SNOW' program my folks installed on the PC.

Please yopur help would be greatly appreciated.
Thanks
Moses