My trusty HP laptop is having a bizarre intermittent problem. It mimics either a RAM fault or over heat condition but is not consistent. System info: HP DV7-2270us notebook PC, Intel Quad core 2.0Ghz, 4 GB RAM, discreet ATI video card (1 mb), Win 7 64bit. BSOD's, app lockups while in Windows requiring hard power down to terminate. Reboot may fail @ black screen before even bios POST and caps lock and num lock LEDs flashing in unison, hard drive LED flashing in orange color (normal color white). If I unplug it and let it sit a while, plug back in, it will start as normal and be stable for anywhere from 30 minutes to indefinite, upwards of several hours. Changed the CMOS battery with new thinking that was the problem. No help. Removed and reseated RAM dimms. No help. The RAM test offered in the POST menu pre-boot declares the memory passes tests. Hard drive test in pre-boot POST same thing-- passes S.M.A.R.T. tests. Have ruled out thermal buildup because it will run stable through demanding apps that spin the fan at max rpm and exhaust hot air out the vent (e.g. Crysis Warhead in 64 bit DX10 mode, or a benchmark stress test app). Then the next day for no reason just idling in the desktop it will either BSOD or otherwise lockup hard. Scans clean via Microsoft Security Scanner, MalwareBytes Premium (registered version), and Kapersky free scan. Last night I regressed the BIOS back to version F.44 (previous ver to F.46) and it has been stable since, but same thing happened when I re-flashed F.46 a few days ago-- it was stable for a couple days through all sorts of apps and then began flaking out again. I will delete all System Restore files in case some malware has hidden there and is able to hatch out of System Restore and wreak havoc, but then it would seem that the scanners would pick up while active. Have heard of rare BIOS infections but would think re-flash would kill that. Unless it's dwelling in System Restore and re-infecting the newly flashed BIOS (?) If that is even possible. The laptop has been in service 4 yrs and 9 months and has been rock stable until this started a couple weeks ago. The battery has been shot for two years now and it relies on AC power. Running with battery removed does not help the problems it has been having. Also possible the AC adapter is beginning a slow decline and randomly sending dirty power bursts or otherwise fluctuating the power quality (?) The MalwareBytes Premium runs real time protection and has been pretty good at catching threats before they can get a foot hold, as well as malicious website interceptions. Just throwing this out there for opinions, has me scratching my head.