Hi - please forgive me joining up and immediately picking your collective brain. Not really sorry but, maybe, a tad rude so thought I'd better say "Hi" first and introduce myself. I used to build my own pc's but have drifted away for the last couple of years. Now that I need to build another those couple of years feel like a lifetime! 
I have a Intel P4 with HTT based desktop in a very nice case. Unfortunately it developed a fault with the M/B meaning it loses the HDD at a whim. As such it has sat in a dusty cupboard for a while. However it has saved my life when my laptop crashed and it was the only thing I could use to get online - meaning I could recover a years worth of photo's and music.....
I've decided it's time to upgrade but have a very limited budget at the moment..
Your opinion:
I need:
new M/B
new (quiet) HDD
new (very quiet) CPU cooling fan
It would also seem to make sense to upgrade the CPU at the same time. I'm not fussed whether it's AMD or Intel based, only used P4 as it was best for video editing at time.
The most strenuous activity for the PC will be video editing home movies to send to relatives on DVD, apart from that mostly used more as a media centre (DVD player, music store and downloaded films) (without media centre OS!!!) and internet browsing. It will have external HDD's connected for additional backup of important pictures etc.
I have around £200, but less is better, to spend and want to concentrate on the M/B (pref with onboard graphics & sound) and CPU. The m/b needs to have firewire.
I know I don't want much!!!! But what CPU & M/B combo would you recommend? And best 500GB - 1 TB internal HDD? I have 2 GB DDR2 RAM which would prefer to reuse but......
Ultimately I will add graphics, sound and upgrade other bits as I go along (and have more cash to spare).
Any thoughts gratefully appreciated.

I have a Intel P4 with HTT based desktop in a very nice case. Unfortunately it developed a fault with the M/B meaning it loses the HDD at a whim. As such it has sat in a dusty cupboard for a while. However it has saved my life when my laptop crashed and it was the only thing I could use to get online - meaning I could recover a years worth of photo's and music.....
I've decided it's time to upgrade but have a very limited budget at the moment..
Your opinion:
I need:
new M/B
new (quiet) HDD
new (very quiet) CPU cooling fan
It would also seem to make sense to upgrade the CPU at the same time. I'm not fussed whether it's AMD or Intel based, only used P4 as it was best for video editing at time.
The most strenuous activity for the PC will be video editing home movies to send to relatives on DVD, apart from that mostly used more as a media centre (DVD player, music store and downloaded films) (without media centre OS!!!) and internet browsing. It will have external HDD's connected for additional backup of important pictures etc.
I have around £200, but less is better, to spend and want to concentrate on the M/B (pref with onboard graphics & sound) and CPU. The m/b needs to have firewire.
I know I don't want much!!!! But what CPU & M/B combo would you recommend? And best 500GB - 1 TB internal HDD? I have 2 GB DDR2 RAM which would prefer to reuse but......
Ultimately I will add graphics, sound and upgrade other bits as I go along (and have more cash to spare).
Any thoughts gratefully appreciated.

