I recently (6/8/08) built a system. The memory available on my hard drive shown by windows DISAPPEARS WITHOUT ME DOWNLOADING ANYTHING. If my computer crashes, if i run a diagnostics, if i defrag, or if i just plain leave my computer on for hours, memory available for my hard drive shown by windows will go down and down and down. It only takes a week for 50 whole GB's to just VANISH. I have NOTHING except for a few drivers and have already reformatted 3 times. Here is the catch, I have tried THREE different hard drives and this happens to ALL of them. The drives have been purchased at different times from different vendors and have all been in the computer individually so I doubt it has anything to do with the hard drive itself. Also all the drives have been good in the past, and i have used one for 3 years with no problems.All drives have passed MULTIPLE diag tools. The Drives are, WD SE16(purchased at best buy), WD RE2(purchased at newegg) and a 3 year old Maxtor(purchased at fry's). The rest of my build consists of:

OS: Vista Home Premium 64bit
CPU: E3110
MB: Gigabyte X48-DS4
RAM: 2x2 Corsair 6400 C4

Please if anyone can help I'd much appriciate it, as no one yet has been able to. I also highly doubt it is the harddrives and am highly suspect of the motherboard. can this be a motherboard issue/ how could i check this?

http://www.tomshardware.com/forum/ [...] a#t1823986

see other post (ie --- tisk tisk, don't double post)