Can't Run PHP Stable With Versions Above 5.0.3

Windows 2003
IIS6
PHP 5.0.3 and PHP 5.2.1 running with the ISAPI dll
MySQL 5.1.11

I kind of have 2 problems, the first being the one in the thread title and the second is while running any version of php my main site experiences slowdowns and hangs.

For some reason whenever I try to install a new version of PHP I have major problems. I have tried several times when new versions come out. I just recently tried the newest, 5.2.1, which I want to try and use, I think there are performance improvements for IIS and windows platform in the new 5.x versions?

Anyway I can install 5.2.1 and get it running, and my sites load, but soon after my main site starts to hang, stops loading or loads extremely slow. I can't figure it out. I even tried using the exact same PHP.ini settings from my old working php install.

So everytime I am forced to go back to the latest version that I know works with my server/sites, 5.0.3 [url]

If I restart IIS the pages start loading fast again right after, even recycling the worker process that the site uses usualy makes the pages load normal again.

I tried setting the worker process to recycle every 60min and to use 2 web gardens. These changes havn't really had any affect for better or worse.

Downgrading back to PHP 5.0.3 seems to run a bit more stable, but even with this version I get these slowdowns now. I have been running my site(s) on this server for 3 years now and most of the time they have ran stable.

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I was sleeping this morning and recieved a text-message saying the site wasn't loading. So I wake up and the site indeed was pretty much not loading at all. I look at permon that I left running to see this: [url]

I give IIS a restart, which you can see above, then the levels go back to normal, here is a screen shot a couple minites later to what the "Current Connections" graph usualy looks like when the site loads fine. [url]

During this slowdown the CPU usage was not maxing out, was maybe averaging 60% and ram was 50%. I am getting a 2nd server soon to off-load the MySQL to it and have it dedicated for that. But i don't think that will help this current issue. Here is the system resources when the site is loading fine: [url]

I have around 40 or so other sites hosted on IIS and my main site "canadaka.net" which is purple on the top graph, is the only one that hangs or slowsdown. When this slowdown happens to this site, all the other sites on IIS, which are on a seperate worker process, continue to load fine.

I can't figure out why these slowdowns are happening.