I read your post and just had a thought, have you condidered* turning off some of the tasks running in your task bar by right clicking on them and using thier pop up menus?
Video conversion usually uses up alot of system resources, it is processor and memory intensive. That's why professionals have super expensive rigs built just for editing videos and converting them.
So, maybe if you tried converting the videos while not running anything else except your AV, and Firewall, in your taskbar. And while not using any other programs it may help.
There is this too, but please talk to an Forum Admin before doing any of the things mentioned here.
Also, I read an article about cleaning out the inside of your computer Here
to help it cool it's self efficently. This does
help, I clean mine out at least 4x a year (I live with 2 very hairy cats, no matter where I put my system unit it gets dusty inside). Make sure you follow the instructions carefully about preventing damage to your computer from Static Electricity (aka ESD) before you open the case by wearing a wrist strap or touching the chasis repeatedly.
I also avoid wearing long sleave shirts when working inside a PC, I zapped a MOBO that way once even while wearing a wrist strap connected to a grounding mat. It was a strange event. I'm still trying to figure out how that happened.
If you don't feel comfortable opening your system unit by yourself find a professional to do it for you.
I'm assuming little or no computer expertise because you did not indicate in your post how much experience you have. Please do not take it personally.
*condidered? LOL I meant considered but it was such a funny typo that I decided to leave it in.
Edited by rsmith12573, 27 February 2009 - 09:34 AM.