Dual Mirror G4 startup issues - Help Please!

I have a Mirror Drive G4 Dual 867, 1 Gig of RAM, running the most up to date version of 10.3.9. Ever since I moved back in January, when I start up my computer sometimes it fails to start up at all (no video signal is sent to the monitors) and the power light blinks red 4 times in 2 seconds, stays normal for a bit, then blinks again 4 times (rinse, wash, repeat). Also, I believe when the problem first started, there was a loud, monotone alert-ish sound/tone from the tower's speaker (if it still happens now, I don't know since I have separate speakers plugged in and they're usually off at startup).

If I hold down the power button and force shutdown the computer that way and restart, the computer is usually fine. However, sometimes the OS (10.3) hangs and takes forever to load the top menu bar and then my desktop icons (this lag is not always after the above incident, it can happen even when the computer starts up smoothly). What's weird is this startup issue used to happen frequently but has quieted down in the last month and half. It still happens from time to time though.

I've been running 10.2 for years before 10.3, so I should have all the superdrive and firmware updates (usually software update catches that stuff, right?) I checked the video card to make sure it hadn't dislodged or anything, and it seems firmly in its connectors. FYI, 10.3 was running on this computer long before the startup issue happened. Is this a motherboard issue? A firmware issue? Other?

Also, on a different note, but maybe related, ever since I upgraded to 10.3 my external Altec Lansing minijack speakers function oddly (if I go back to 10.2 they're fine). What happens is that they start up all blown out and crackly. If, however, after the desktop has loaded I unplug them from the computer output jack and plug them back in, they reset to normal volume. What could be causing that (especially since it seems to be OS related)?

Art-man