I upgraded the RAM of my laptop to 4 GB by using two RAM chips with the following specification:
Storage Capacity: 2 GB
Memory Type: DRAM
Technology: DDR2 SDRAM
Form Factor: SO DIMM 200-pin
Memory Speed: 800 MHz (PC2-6400)
Data Integrity Check: Non-ECC
RAM Features: Unbuffered
Supply Voltage: 1.8 V
Compatible Slots: 1 x memory - SO DIMM 200-pin
Since I upgraded my RAM, Ubuntu freezes every once in a while. When Ubuntu freezes, I shutdown down my laptop and reboot using the Ubuntu live CD to check for file sytem errors. Then, I run the fsck program, and it discovers and fixes some file systems errors. Then, I run the badblock program. But, badblocks does not find any problems. I believe the fact that badblocks does not report any problems shows that my hard disk is healthy. And, the filesystem errors seem to be due to the forced shutdowns.
I'm using 64 bits Ubuntu 10.04 lucid with kernel 2.6.32-33-generic.
How can I troubleshoot this problem? How can I find out why my Ubuntu freezes? What log files should I consult? What should I look for in the log files to find the cause of freezes?