A few months ago I replaced my Toshiba Satellite A665 hard drive. A couple of weeks ago I upped my RAM from 4 to 8Gb. Is it a coincidence that shortly thereafter it started not to boot properly? When I wake it up from sleep the hard drive starts to spin, then it suddenly goes black, and then the (safe mode) window with the "start windows normally" highlighted appears. I click and it starts up again but anything I was working on is now gone.
Have you tried removing the new RAM to see if that may be the cause of this problem? Intermittent RAM problems can cause this sort of behavior, especially since laptops don't have ECC (error-correction) memory. If it has an occasional glitch, then this sort of behavior is not unreasonable to expect.
If you have added 4gb then remove the new ram..maybe they are 2 different brands working at different frequencies i mean 533 and 800. I suggest individually trying both for a day each. May be same brand ram can be used or same frequency (mhz) rams must be used. Some RAMs will give display but still in the running will give a problem due to mismatch of frequency with motherboard or with partner RAM.
Thanks everybody. Windows 7; detected: says "8gb"; had 2 slots, I removed the 2 2's and installed 2 4's. New RAM is the first thing I thought of, so I did install the old RAM again. It still happened so I put the 8 back in. This happens when I wake it up: I hear the hard drive start to spin and it's noisy (but all my Toshibas are noisy), I get the login screen and start to type my password, then all of a sudden the screen goes black with cursor flashing, then I get the "safe mode" black screen that says Windows didn't boot properly and the "load Windows normally" is highlighted. I click and it loads. Since all my programs and browsers are now closed, this is really annoying. I have no problems starting it from a cold boot and once it's running, also no other problems.