Have to reboot computer (Vista) 10+ times before it's stable enough to use

I'm using Vista, which is terrible, but I don't have the funds for a new OS right now. The problem is that I'll turn on my computer, and it loads up just fine, I get all the way to my desktop, but about a minute later, the whole system crashes, not even a BSOD to give me a clue as to why.

So then I open it in safe mode. Same thing happens. I reboot again, and it won't even take me to the boot mode selection screen. I turn it off, wait about ten seconds, reboot. It repeats the same cycle about twice before finally giving up the ghost and running smoothly. At that point, I can run it as long as I want, no problem. I can't put it in sleep mode, though, or it'll crash.

I've run chkdsk countless times, several registry fixers, virus checking programs (all of which were from trusted sources), and I'm virus-free. I only found a few minor registry errors, but these clearly weren't the issue, as my computer still buggers up. This started happening at the end of December and I don't know why, as I hadn't downloaded any files or messed with the system at all that month. I was away on vacation most of the time.

I'll post the six recurring errors that appear in event viewer that happen just before the system shuts down after seeming okay. There are about 20 others that sometimes occur, but they seem to be a result of the system shutting down, and not the cause.

DCOM got error "1084" attempting to start the service WSearch with arguments "" in order to run the server:
{9E175B6D-F52A-11D8-B9A5-505054503030}
DCOM got error "1068" attempting to start the service netprofm with arguments "" in order to run the server:
{A47979D2-C419-11D9-A5B4-001185AD2B89}
DCOM got error "1068" attempting to start the service netman with arguments "" in order to run the server:
{BA126AD1-2166-11D1-B1D0-00805FC1270E}
DCOM got error "1068" attempting to start the service fdPHost with arguments "" in order to run the server:
{145B4335-FE2A-4927-A040-7C35AD3180EF}
DCOM got error "1084" attempting to start the service EventSystem with arguments "" in order to run the server:
{1BE1F766-5536-11D1-B726-00C04FB926AF}
DCOM got error "1084" attempting to start the service ShellHWDetection with arguments "" in order to run the server:
{DD522ACC-F821-461A-A407-50B198B896DC}

A side note: There are a few recurring errors here and there outside of the ones that result from crashes, and they all have something to do with networking. This is strange, as I start safe mode without networking and it still shuts down. Another interesting thing about it is that sometimes, the system will be fine on the first startup and I'll go get food or something, and when I come back it's working well. But when I start up Google Chrome, the system shuts down. (I've reinstalled it twice and used firefox and IE to see if it was Chrome' doing, but it appears to be any browser that shuts it down like that.)
 
Laptop or desktop computer? If it is a desktop, the power supply might be the cause of the trouble
 
Well then you might have a friend who knows computers swap that power supply for you. good luck :)
 
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