Alright, so since I'm the fucking tech help for my entire goddamn family, I have to try and fix their computers after logging for 10 hours today. So this is a Dell PC with Windows Vista... maybe six years old or so. Lately it's been shutting down... now it may or may not have at one point said "shutting down to protect windows", or something like that. However the last time it just went into normal shutdown procedure (showing the Windows "shutting down" screen), but it sat like that for hours. Then at some point it goes into the F2 boot setup menu by itself, where I noticed it says "no bootable hard drive". Manually turn off the computer and restart, and it works fine (for a while at least). Any idea what is going on? I looked through the event log, but I don't know really what to look for (nothing stood out). I did install new RAM around two months ago, but it worked fine after that. I've scanned with MSE and Malwarebyes. MWB found one thing, but removed it successfully (forgot to write down what it was). This computer is used almost exclusively for checking a Yahoo email account and balancing a checking account via Quicken.