I recently upgraded my Dell Dimension E510 from Windows XP Media Center to Windows 7 Pro 64 bit. Before doing that, I also upgraded the memory from 4gb to 8gb (4 sticks of 2gb). I upgraded the memory first and it worked fine with XP. When I first inserted the CD to upgrade to 7 with 8gb it wouldn't go past the black "Starting Windows" screen. There was no logo or anything. I removed 2 of the 4 and restarted the setup and Windows 7 installed fine. After the setup, I put the other 2 back in, so all 4 were in, restarted the machine and I got the same black screen at startup. I removed the original 2 and replaced them the with the second 2 and it started up just fine again. I've tried every combination (even 1 at a time) and every time it started fine, just not when all 4 are in. All 4 sticks are exactly the same. The BIOS recognized all 4 when I had them it. The processor is a 64 bit Pentium 4. I'm at a loss on why all 4 wont work at the same time. Any suggestions/help would be greatly appreciated.