Having a bit of trouble with IE6 on my machine (specs below).

Since I formatted my hard drive not so long ago, and installed WinXP Pro, I've been having trouble with IE6. Browsing is fine, in fact it works a treat when its open, but I'm having problems opening webpages... here's an example:

Instead of clicking the IE icon and opening up my set home-page, I browse to my favourites and select the site I want to view (at this time there is no other IE page open). Sometimes it opens as normal, but every now and again when I click a link in my favourites (no particular sites, it happens randomly) the system will freeze and no IE page opens. This lasts for about 10-15 seconds, then its like as if the system catches up with itself and IE opens the page, service resumes as normal.

That's not the only problem IE is giving me though. Most of the time (but not every time) when I shutdown, I get an error along the lines of "IE is not responding properly" and I can click "End Now", or wait for about 15 seconds, then the computer shuts down as normal!

Are these problems linked? I've asked about this in several other forums and took the advice people have given me, which includes:

Installing SP1 - Done that, made no difference.
Downloaded the Java Runtime 2 Environment - Someone suggested a java problem - it didn't fix it if it is a java problem.
Repairing IE - Tried this, and it didn't fix either problem.
Downloaded all Critical Updates - done, not fixed.
Do a virus scan - done two and neither came up with any viruses or trojans.

I'm running out of ideas, and if push comes to shove I'll format my drive and put XP back on, but I only want to do that at a last resort.. surely there's a fix to this?

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System Specs:

Win XP Pro
Gigabyte GA-7ZXE Motherboard
AMD Athlon XP 1700+
320MB SDRAM
40Gb Seagate Hard Drive
128Mb nVidia GeForce 4 MX440
Soundblaster Live! 5.1 Sound Card