New build problems

[padlius]

I have built the computer for someone, he ordered all the parts I told him to do exept I assumed that his case wont be pain in the ass and his power supply will be bit bigger than 300w. I in the end built it and now it keeps crashing. What is the cause of that? Is it either not enough power, but it works fine sometimes or I may have damaged the processor pushing on the heatsink on. Thanks

 

[mdd1963]

More details needed...

Some systems might run with a 300 watt PSU, but, that would be marginal for a modern system with most mid-range/upper mid range GPUs today....

Does it POST? Can you even enter the BIOS? Does it hard 'power off' on it's own?