Alrighty, I think I should start from the beginning. I hope posting this helps because I'm just about to implode. Ok, I've decided to buy a new computer. I have just received it before yesterday. it's a Pentium4 2ghz processor with 192mb of ram, also has built in video, sound, and modem into the mobo. Also comes with a 20gig western digital drive as default. On to the problem and what might have caused it. Upon purchasing the new system I had in mind replacing the new HD with the Maxtor 40gig drive I had in my old system(which also had xp in it), so I did. Something came up(blue screen problem with the hardware incompatabilities crap, but I was going to format the maxtor anyway). I formated my maxtor drive so it wouldn't cause any incompatabilities with my new mobo, however, I put it in slave mode with the new drive because the new drive that came with the system already came with XP home edition installed. My plan was to take whatever important files I had in my older drive and back it up in the new drive which was in master mode so I could then install xp pro FROM the new drive into the old one and put the old one back into Master as it was in my former system. So when at last my 40gig maxtor would be in master mode and the new drive in slave, I'd just put my backup into the maxtor drive again right? Sounded like a plausible plan at the time. So, I did that. I made a new installation of XP pro into the old drive from the new one and each time I would reboot I'd get a choice of OS to use. After that was all said and done I tried to format the new drive from the old drive from xp pro while still in slave mode. It seemed to be working(I right clicked format in xp) until at the end of the format it said it was unable to complete the format, so I decided to just shut down the system and take the new drive out and put my old drive in primary master mode so I could simply start up the computer directly into xp the next time. Well, it didn't. When I booted up, it was looking for something to boot up from the cd-rom, I tried changing my bios settings to boot up from maxtor but it still kept asking to insert the right system disk. If I pressed enter to skip it, it would say it couldn't find NTSF(something of the sort, I think it has something to do with the format types like fat32 and such from the xp install). Nothing could be done from here on, so I put the new drive back in figuring it might be a dual-boot issue that I had to take care of, but to my surprise, after installing all my drives back in like they were when they still functioned correctly, the dual boot screen appears asking me which OS I want to use, I chose either one and they both freeze into a black screen. I tried using the last good restore, and a list of files appear and it freezes at mup.sys everytime. All of the options do not work, including safe mode. I need to know if there's anyway to remedy this awful situation of mine. Should I format both drives and start clean? If so how do I format if I cant reach fdisk from dos? Can I re-install xp? Is there a way to confront this mup.sys file? Have I damaged my Hard drives in some way? I have a recovery disc that came with my system from the vendor, I didn't use it yet, but I really wish I could keep my backup on the new drive too... Please help me out, any help is greatly appreciated.

Everything you tried I would highly recommend against if someone asked me. What you should have done was to clone the OS using software like Norton Ghost then install it on the 40gb drive. That is what I got from your mini-novel anyway ; ) On to the matter at hand... Because you cannot boot back to last known good configuration, I would guess that the data on both drives is hosed and you would have to reformat/reinstall. No, the drives should be fine. Mup.sys issue; no idea how to bypass the error. Perhaps someone else may offer a suggestion. Fdisk? You don't need Fdisk. You can boot to your CD Rom and create partitions/format using the XP CD and go from there. If you want to use Fdisk, you can load a Windows 98 boot disk and do it that way. Else, you can make one from http://www.bootdisk.com/ Good luck.

i would put the big hard drive in the new system , ,and install xp fresh. This is a great time to experiment and have some fun and learn. If you don't have an xp install disk see if you can get one from the vender you bought the systen from, if you only have a system restore disk from the vender, use that. You are already in a mess, your drives are fine, what you did didn't damage them, the file system and files just are mixed up or not right for you new set up. Take this time to try different install methods and different hard drive set ups. Take a weekend and try it. It can take 1-2 days to fully set up and install all your software to your likeing. I have found tat system set ups from venders is usually buggy and not as good as a regular xp fresh install from an xp disk. xp pro is very smart and can fully install and set it self up with your installed hard ware. never back up to hard drives alone!!! anways back up to removable storage { like cds }