XPS 1555 shutdown during boot and error code

My brother applied Arctic Silver 5 on this laptop, which previously had overheating issues. The previous thermal compound on it might as well have been dust. Now the laptop boots but shuts down before it can boot into Windows, it shuts down no matter if it is running a diagnostic test, booting off of CD, or booting into Windows. The bottom of the laptop is ice-cold, which makes us think that it isn't overheating. We have removed the WLAN card and have a single RAM chip in the laptop, to rule out anything possible. What can be causing this? The error code given is C000021A.

 

I would first try;

Removing battery and AC adapter, hold down power button for 30 seconds.

Reseat RAM module(s) and hard drive

Use known good RAM.

You also could have botched the repaste job.

 

You tried safe mode by using f8 then use a restore point?

 

Thanks for the replies.

We disassembled and reassembled the laptop, it turns out that when my brother put new paste on the GPU it didn't make contact with the heatsink because it had a thermal pad on before, which obviously had a higher higher than the paste does. Some work and a little later, the GPU now makes contact with the heatsink.

Booted right up and the laptop went from overheating during flash games to a steady 45 degree idle. We can assume the GPU was in fact overheating, although it's strange that the air coming out was ice-cold.

 

Odd I haven't seen an overheating GPU prevent Windows from starting up. Normally it would have let you boot and you might get artifacts or instability. Well that's good to hear.