This is a bit of a weird question now... so bear with me. I upgraded my girlfriends PC to an AMD 2000+ & Gigabyte GA-7VA (donated from my m8 when he got his 7NNXP) on Saturday and it worked fine... Installed it, ran it Saturday night and Sunday all day. However, when she turned it on on Monday (around noon), it wouldnt detect the HDD. I thought "ffs, same scenario as mine" (I'll go onto this in a sec) and looked onto PC websites to find a decent replacement... I turned it on in the evening only to find it booted fine with no problems. I ran the Seagate diagnostics CD (downloaded from Seagate website for this model drive) and it came up all-clear. Now I'm really puzzled. How come it did that? (not detected HDD). Anyway, onto my PC. I upgraded my system to a P4 2.4ghz and Gigabyte GA-8PE667 Ultra mobo a while back. I built and installed it on Saturday, ran it Saturday night and all Sunday. Monday when I got home from work, I turned it on and the HDD wasnt detected. I was a little confused and p*ssed off to say the least, but went to the computer shop in my lunch the following day and got a new HDD. I got home and switched the PC on to see if it was still messing around and it worked fine... I ran scandisk on the drive and it came up all clear. Has anyone had a similar problem in the past? Why does it do this? Is it common?