I have an Inspiron 1545 that randomly shuts off, but not in Safe Mode. I have already done the following:
1) Removed bottom cover and cleaned the cooling intake (it was very clogged). I feel the air circulating, so the fan is functional, and overheating is not a problem.
2) Suspected corruption of Vista, so I backed up data and wiped out the system. It powered off in the middle of the Vista install, so it got corrupted and I had to start again. Thankfully it made it through the installation the 2nd time.
3) Ran onboard diagnostics. It shutdown in the middle of the March B memory test, every time I ran diagnostics. Suspecting a memory problem, I removed existing modules and inserted a brand new 2GB module. Shutdown still occurred. No error code or indication of a failure, it just shuts down. This occurs both on battery and on AC power.
4) If I boot to Safe Mode, it stays on indefinitely.
5) If I boot normally and don't touch it, it stays on. If I try to do anything, such as download Windows updates, it will instantly shut off within a few minutes (the timing is random, but always within 10 minutes and usually within 1 or 2 minutes). Again, no warnings or indications of an error, just instantly off.
I suspect a problem with the System Board, but before I spend the money and the time replacing it, I want to make sure I'm not missing something else. Any thoughts?