HP Computer issues [plz read]

[jaguarman]

This is one of those older HP Pavilion desktops...
I received someone's desktop to fix, I attempted to start it, it was on for maybe 5 seconds and shut down by itself. It wouldn't start again.
I took the hard drive out and plugged it into my laptop using a USB to SATA adapter cable, scanned it with Microsoft security essentials, found 2 threats, i had it remove the threats. I plugged the hard drive back into the HP Pavilion and it started up fine. I started to do a scan with the Microsoft security essentials installed on the HP, it scanned a little bit and shut down. I or it then started back up and the HP logo screen now has white lines on it...
IT then goes to a "Choose an OS" page and it automatically goes to the bios page where you choose "Start windows normally", "Safe Mode", etc.
It also gave me a choice of "Go back to last configuration settings" and i selected it. No help, it didn't solve anything. I don't know what was happening before i received it.. all i know is the owner thought it had a virus and couldn't get it to do anything..
Thanks for reading all this stuff

 

[TheDraac]

The first thing I would check if it is shutting off so quickly, since you have the case open already, check the CPU cooler to see if it's loaded with dust.

An "older" system shutting down like that is usually heat related. Blow it out with an air duster.

Let us know if that changes anything.

 

[jaguarman]

I looked at the CPU fan and it doesn't seem clogged with dust at all, the system doesn't even seem very dusty.

 

[jaguarman]

The first thing I would check if it is shutting off so quickly, since you have the case open already, check the CPU cooler to see if it's loaded with dust.

An "older" system shutting down like that is usually heat related. Blow it out with an air duster.

Let us know if that changes anything.

UPDATE
I unplugged the power cord going to the hard drive and plugged in a different power cord, resulting in the computer functioning correctly.
The power cables in this computer are a real pain to get into the ports on the devices, I guess I didn't have the other power cord shubbed in enough.
Does this sound like an accurate theory?

 

[TheDraac]

It's odd that if it was just the power cable issue (not being plugged in fully), that it would manifest itself by having the computer shut off. I would think if would boot up be unable to load the OS.

However, if plugging the hard drive into another power connector fixes the issue, I guess you could leave well enough alone.

As for you choice of virus scanning, I would suggest the Eset Online Scanner. http://www.eset.com/us/online-scanner/
As well as AVGs free Antivirus. http://www.avg.com/us-en/free-antivirus-download
Both are free and work very well and are much better in my opinion that MS Security Essentials.

You might also try HDTune to test the hard drives integrity. http://www.hdtune.com/
The free version only works for 30 days, but for testing on a single computer it should be adequate.