The New Computer Saga

So, I went in and ordered a new computer on Monday.. It was supposed to have a super motherboard with onboard lan, 256 mbs of memory, 80 gb hard drive, awesome cd writer, Windows XP, he could put my old hard drive from my old computer in it, and he could have it ready for Wednesday.. I thought cool... two days and I'll have a new computer... I told him I'd be in Thursday morning to pick it up, Thursday, because my pay didn't come in until midnight on Wednesday.. He called me on Wednesday afternoon, and told me that the cases he ordered had been damaged in shipping, but there was one already built in Summerside, and it was on it's way up for me.. he told me I could get it sometime after 2pm on Thursday.. I didn't think anything of it.. I went in on Thursday to pick up my brand spanking new computer... first thing he tells me is that Windows XP is not installed on this computer, but Windows 2000 Professional is instead.. again, I thought nothing of it.. I figured I could set it up as a dual boot system, windows 2000 pro, and windows xp home.... I left the computer store and went right to future Shop and bought a router and a wireless usb adapter.. I already had some cabling that I was going to use to connect the router to one of the computers... so, we went home... the first thing I wanted to do was to get the two computers to "talk" to each other... with one computer being windows XP and the other being windows 2000, I couldn't get this to work, no matter what I tried to do... the first thing I tried was a direct connection between the 2 computers with the network cable..I ran the network connection wizard on the WINXP machine, no problem.. when I put the disk into the WIN2000 machine and tried to run it, it told me that the network setup wizard for WinXP worked only witn with Win98/ME/XP, not Win2000... so, I thought, ok.. I'll just set things up manually.... but no matter what I tried to do, the computers just didn't see each other.. I also noticed that every 20 minutes or so, the Win2000 machine would freeze.. The next thing I did was break out the router to just get the computers connected to the internet.. I plugged the adapter into the Win2000 machine and installed the drivers... no problem.. everything seemed ok, except I wasn't getting an ip... I plugged the cable that was connected to the WinXP computer into the router, and bingo.. I had an ip and pages... So.. what was I doing wrong?? I went onto the internet and started reading through the user guide on the page for the router... I found step by step instructions on setting up the adapter.. cool enough... I went through them and I finally was able to get both computers connected to the internet... Now, that was fine and dandy, except that it was set up the wrong way.. I wanted the adapter on the WinXP machine and the cable on the Win2000 machine... so, I unplugged the adapter from the Win2000 machine and plugged it into the WinXP machine, then began loading the drivers... all of a sudden up popped a message saying that the drivers that I was trying to install needed WinXP SP1 in order to install properly... now, as far as I knew, I had SP1 already, but I started downloading it again just to be sure.. for about an hour I sat and watched that blue bar crawl across my screen.. Then, when it looked to be almost finished, it froxe up, didn't move at all... I got tired of looking at this after a while and just shut the computer down.. I left them alone and watched some tv for a while and came back to them.. I turned the WinXP machine back on, and for the heck of it, tried installing the drivers again.. this time, they installed... I set up the adapter to connect to the internet, and again, had 2 computers on the net.. I decided that that was enough for now, and went to bed... In the morning, I decided that I'd try and set up my new Win2000 machine as a dual boot machine... I did a search for the boot.ini file, and didn't find it at first.. I wrote in the command to select the other operating system on the machine, saved it and restarted.... the page came up asking me which operating system I wanted, Windows 2000, or Windows XP.. I clicked on Windows XP, and got a message saying that it could not be found.. I rewrote the boot.ini file to specifically look for the windows file, but it still didn't work... I again gave up on this and left it alone..
This is as far as I've gotten so far.. Since it freezes up so much, I'm thinking of taking it back... I also want my Windows XP.. I'm sure I'll be able to get everything working once I have XP installed...
Anyone have any tips???