System glitchy

[#1]

Hi all
I used to use an AMD 1.8GHz Athlon with a whopping 1GB ram. It was fine, worked flawllessly but the CPU fan noise made Heathrow sound quiet.
So, I'm now (courtesy of the local freecycle) using a 2.8GHz Intel Celeron D. Again 1GB ram.
It's been glitchy for ages and I always thought it was just the OS being rather old and needed reinstalling. I'd also had VMware mess it up with USB etc so I just put up with it.
About 3 weeks ago I reinstalled XP as I'd finally had enough. Today getting fed up with the glitches on youtube videos I ripped out my nVidia FX5500 from my old machine and put that into this one to replace its crumby old gfx card which was nowhere near the same spec.
I'm still suffering glitches - badly. Would I be right in thinking that the Celeron D has a rather low cache which is probably causing a system bottleneck for graphics? - Having been an AMD man for many (noisy) years I've never had to put up with this before.

[#2]

On You tube?
I would try playing a DVD or downloaded video file.
And then do a ADSL speed test.

[#3]

I was connected at 6Mb at the time so I don't think its a speed issue. Also the red progress bar on the youtube player showed there was adequate buffer to play but its just glitchy all the time and its driving me mad.
I just wondered if this might be a level 2 cache problem due to it being a celeron processor. I'm sure its a processor issue because when watching a local video from my hard drive clicking on a hyperlink on the other monitor causes similar effects.
I know 1Gb isn't much ram but it should still do the job - my 1.8GHz never had this trouble.

[#4]

I've got an old (circa 4 years) Windoze XP which starts and runs very slowly, but without You Tube glitches.
It is only 512MB, but Windoze snatches some of that for video.
My other PC's are Linux.

[#5]

I don't know what It sounds like the problem could be but I am certain Its not your Ram stick.

[#6]

Have you updated video drivers?

[#7]

Actually thats a fair point Penfold because no I haven't. I stuck the gfx card in and windows recognised it so i just let it do its thing. I've not been able to find the box with the CD in it.. I thought it was under the stairs with the millions of old computers that are now dormant since my network was dismantled but when i looked it wasn't there. I suppose I'll have to dive in there again and have another look but its literally like exploring a jungle..

[#8]

you should still be able to download them from the nvidia site.

[#9]

Alternatively, try running You tube from a Linux bootable CD and see if it still glitches.