PC crashing in single channel mode

[tgbyhn10111]

Hi

My PC was crashing so I ran memtest on ram. One stick failed in all 4 slots, the other worked in all slots so I thought I'd found the problem.

I put the goods stick back in and started working in single channel mode but I'm getting the blue screen of death saying there was a hardware fault. I know I've got the good stick in because I marked the bad one and I've retested it.

Are boards less stable in single channel mode?

Any one got any idea what's happening?

The system is overclocked the same as before to 3ghz all settings the same is that OK in single channel mode?

Help...

my system

Intel Core 2 Duo E4300 1.8GHz @ 3GHz
Gigabyte GA-P35-DS3P
Sapphire X1950Pro 256MB GDDR3 DVI TVO HDCP PCI-E Graphics Card
2 x Raid Seagate 160GB 7200.10 7200RPM SATAII/300 8MB Cache - OEM
1 x Seagate 7200.10 320GB SATAII/300 8.5ms 7200RPM 16MB Cache - OEM
2 x Corsair (CM2X1024-5400C4) 1024MB, DDR2-5300/5400 (667/675MHz) Twin2X Matched Memory Pair
1 x Lite-on 16 X DVD-ROM SHD-16P1S
1 x Lite-on DVD-Writer SHM-165P6S
Arctic Cooling Freezer 7 Pro