Recently I had a complete clean out inside my PC (completely dismantled then pieced back together). I had a few minor problems to begin with, but had it working in no time. It was in use all day yesterday with no problems whatsoever, however come this morning, I turned it on and to my surprise it failed to load Windows (XP). It gives me no warning however, but when the screen with the devices appears (it has all the things like USB and parallel ports etc in a table. IRQs? I think thats the term), it gets to the bottom of the screen and all I get is a little flashing cursor towards the left of the screen beneath the table. I cannot type anything on there either. I have left it for a few minutes, but it just doesnt get past that point (no error messages at all regarding HDD boot failure). I have not changed any settings at all up to this point. I checked inside my PC (assuming it was a hardware problem) and swapped a couple of IDE sockets/cables around (the drive appears in the list at startup though, so I dont think theres anything wrong with it being read). Still no luck. I had a look in BIOS, but honestly didnt think that anything I did would make any difference seeing as it worked the night before and I hadnt actually changed anything. The next thing I did, I unplugged my HDD from the Motherboard altogether. At the end of the IRQ (?) screen/table, instead of receiving a flashing cursor as before, I received a message: "Error finding system disk" (with reference to DVD/CD drive) or words to that meaning. It then prompted me to insert a disk. I then swapped the DVD drive with the HDD (HDD is now plugged in the IDE socket that the DVD drive used to be in) and Windows booted as normal. Does anyone have any idea what might have caused this problem to occur? For the record, I did install a new HDD drive (besides the one with XP on) yesterday, but had no problems with that at all. Even after removing it from the system just now made no difference, so I doubt it is to fault as the problem still occurred with its absence. I have a Gigabyte 81915P Duo Pro Motherboard and have windows on a Maxtor 6L200P0 HDD. This HDD is plugged into either IDE 2 or 3 and the DVD drive is plugged into IDE 1. At the moment, Windows is working having the HDD plugged into IDE 1. Thanks in advance!