Did you just reinstall over top the old Fista, or did you completely format and partition the hard drive before install? I Always recommend a fresh install over reinstall, traces of old logs and files do stick around with reinstalls because its trying to save some data for re-use while replacing others and doesnt always get it perfect. As far as memory goes, isnt this what you have? http://www.ocztechnology.com/products/memory/ocz_ddr2_pc2_8500_reaper_hpc_edition I'd also recommend running them at the 555-15 @2.1V like the webpage specs call out. Run tests. If that doesnt work, change that memory multi from 3.2B down to 2.4B and try running at 800mhz instead of 1066. Run tests. Between Sam and I we should be able to stabilize your system if doing anything aside from buying new sticks on the boards list will fix it.