Weird harddisk problem

I'm having problems with this 80GB WD IDE harddisk I purchased 6 months ago. It was working perfectly fine until recently. Nowadays it suddenly disappears from Windows and BIOS without a warning. Then I turn my system off for a few minutes and then turn it back on and it's working again. I have Ariolic ActiveSMART software installed and it shows no problems with that particular harddisk. My system is an Intel 865PERL motherboard with P4 3Ghz HT, running a Windows XP Pro with all the updates installed for hardware and software.

I will appreciate any help/suggestions to resolve this problem

Have you checked the ribbon cable to make sure its securely seated? If it passes S.M.A.R.T. tests but occationally fails thats the first place I'd check. If that doesnt' fix it, try an entirely new ribbon cable. Also be sure to check the molex connector.

I checked the cable and it was securely seated.,

Here is an update: I think I narrowed the problem down to IDE0 port. Here is what I did... First I had the harddisk on IDE0 port and it was disappearing out of the system erratically. So I swapped ports and connected harddisk to IDE1 instead and connected my DVD drives to IDE0. This time I started getting erratic system crashes but harddisk was working fine. So finally I removed my DVD drives from IDE0 and left IDE0 completely open. My computer has been running with full load for at least 8 hours now and I experienced none of the problems I mentioned earlier on. This tells me that there are a few possible causes to the problem I was having:

1- IDE0 is damaged and acts erratic (most probable cause)
2- Maybe DVD drives were consuming too much power and when I plugged them out it eased the system (I have a 450W PSU with 8 fans, 3 harddisks, a DVD-reader and a DVD burner)
3- One of the DVD drives caused things to mess up right from the beginning (since they were always connected to IDE1 or IDE0 when I had these problems.

Which do yo you guys think is the real cause of the problem ? If IDE0 is damaged can IDE0 work but work erratically, and could IDE1 still work when IDE0 is broken ? That's the only thing that puzzles me with the first idea.