Boots With Chime But No Video

If a computer is not plugged into AC power for a while, the internal memory battery dies or gets weak. The memory settings can be lost or get corrupted, and cause startup problems. You probably need a new battery, but first zap PRAM. See Mac PRAM, NVRAM, CUDA/PMU & Battery Tutorial

Besides the sporces in the tutorial you can get one at a local Batteries Plus store FYI, here's the part numbers & prices.

1/2AA 3.6V Lithium, P/N LITHS14250BA, $8.99 + local sales tax
4.5V Alkaline, P/N COMP3LF22BP, $14.99 + local sales tax

Cheers, Tom

Any computer with an unknown history is likely to have a bad Parameter RAM backup battery, especially after it has been off in a box.

The parameter RAM is normally maintained by a tiny always-on supply in the power supply. When the battery is weak, any time the power is interrupted, corruption can creep into the PRAM. Jim (Apaloosa Mac Man) loves to remind us that these batteries are not strictly necessary in most Macs. But having a good battery does make your Mac more convenient to use.

When you service your Mac, often the plug is pulled. Folks forget that without power or a good battery, their PRAM can become corrupted.

An easy (no opening up) way to reset the PRAM is to start from Power off, hold down 4 keys: Command Option P R and press the power key on the keyboard to start up. Keep holding the four keys for over a minute, and hold them until you have heard the chimes four times. Your parameters will be set to defaults, and the Mac will rediscover the Hardware automatically.

Using a display card complicates things a bit. The Mac wants to set up your two displays into an extended desktop. It is possible that the Apple menu is stuck on the unused built-in display. Sometimes just leaving no adapter on the built-in display will cause it to be ignored.