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Computer completely locks up at random unless in Private Browsing mode

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For several weeks now I've been having a complete lock up of my computer (Dell Latitude D630 running WinXP SP3) at random when browsing the internet using Firefox. It usually seems to happen while a page or image is loading, and when it happens the screen just freezes up and the computer is completely unresponsive. I have to perform a hard shut down and reboot.

If I use Private Browsing mode it doesn't ever seem to happen, and it doesn't happen while using IE or Chrome at all. I just finished a complete wipe and reload from scratch of my system in hopes of fixing a possible virus, but it continues to happen.

For several weeks now I've been having a complete lock up of my computer (Dell Latitude D630 running WinXP SP3) at random when browsing the internet using Firefox. It usually seems to happen while a page or image is loading, and when it happens the screen just freezes up and the computer is completely unresponsive. I have to perform a hard shut down and reboot. If I use Private Browsing mode it doesn't ever seem to happen, and it doesn't happen while using IE or Chrome at all. I just finished a complete wipe and reload from scratch of my system in hopes of fixing a possible virus, but it continues to happen.

All Replies (6)

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I see that you have disabled automatic cache management.

Does this still happen when you enable this and set the maximum a bit higher (e.g. 100 MB)?


In Private Browsing mode Firefox doesn't use the disk cache.

You can try to clear the disk cache, possibly also on your hard drive (see about:cache for the location).

  • Firefox/Tools > Options > Advanced > Network > Cached Web Content: "Clear Now"
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I actually had been using the automatic cache management until just before I posted the question, and turned it off to see if that would help. I increased the size to 500 Mb when I turned it off, but I've already had a lockup again since then, so that doesn't seem to have helped...

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Boot the computer in Windows Safe mode with network support (press F8 on the boot screen) as a test to see if that helps.

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That seems to be working... I had to switch back to Windows' wireless management rather then the Dell utility to connect to my wireless network though.

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Which security software (firewall, anti-virus) do you have?

Does it has any advanced settings that might involve checking files in the cache?

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I'm using the standard Windows firewall and AVG 2013 Free version. In the Advanced Settings of AVG is a Cache Server section, caching is enabled, as is the checkbox for "Enable adding new files into the cache".