I am facing a strange problem from last few months. I have 2 HDD in my PC. Both from Seagate. The older one, around 3.5 yrs old now, I use for installing Windows XP. Its a 80GB SATA HDD. Sometimes it makes strange noise, and the hard drive spin ups & spins down.When I restart my PC, it does not detects the drive. The same symptoms continue after restart. Then if I take out the HDD, & gently tilt it upside down & back, and then put it back, it starts working.