I bought my mac mini in March 2011. It's a mid 2010 model with 2.4Ghz and 2GB RAM.
It came with SL and I immediately installed BootCamp and upgraded it's memory to two 4GB, low latency Corsair.
One day, out of nowhere, I got a kernel panic the OS X partition stopped working. The Windows partition worked fine, though. I tried repairing permissions but it seemed to be beyond repair.
I ran a mem test and got a warning. I figured my RAM was faulty, so I switched back to my old 2GB memory that came with the mac, but I got the same error in the mem test. (Really strange).
I formatted the whole system and reinstalled Snow Leopard, put back the 8GB RAM and ran the mem test again, and it passed 100% this time.
I kept using SL for a few months without any problems (did't bootcamp this time) and then OS X Lion came out. I installed it and started having problems again:
When I download big .rar or .zip files, after uncompressing them, I sometimes get CRC errors and checksum problems.
My Shockwave Flash started crashes constantly a lot under Google Chrome.
Occasionally, my screen becomes "pixelated" in random areas (the image gets distorted as if it was magnified and then pixelated).
When watching movies in VLC (mkv, avi, etc) the video becomes pixelated sometimes.
Applications quit unexpectedly sometimes.
Did a clean install of OS X Lion, and the issues improved to a certain degree, but still occurs sometimes. I can't really pinpoint the issue. At first I thought it was Mem, then I thought it was the OS, now I don't really know what could be happening.
Thanks for the help!