whilst upgrading to Vista from XP I found out that the memory on my laptop was only 512 mb. I was very surprised to learn that it only had 512 mb because I always thought this laptop had 1 gig of memory. My laptop is a Fujitsu Siemens AMILO 3438m with 80 gig hard drive and what I thought was a full gig of memory. So bought a gig of memory from Internet and read about how to install memory. I did everything by the book. I opened the back but opened the hard drive compartment first and disconnected the hard drive. On seeing my mistake, I re-connected the hard drive and opened the second part, where I found that there were two memory modules, both with 512 mbs. First of all, why did it only show that I only had 512 mb when it actually did have 1 gig? I then removed one of the 512 modules and replaced it with a full gig, now making it a gig and a half of memory. I put everything back together and my laptop would not start. I have replaced the original module but it still would not start. What have I done? Any help would be appreciated.