Do you have that problem when running in the Firefox SafeMode?
http://support.mozilla.com/en-US/kb/Safe+Mode
Don't select anything right now, just use "Continue in SafeMode."

If not, see this:
http://support.mozilla.com/en-US/kb/troubleshooting+extensions+and+theme...

It still does the same thing in SafeMode. In fact, yesterday when I rebooted my computer everything worked correctly, but now again today it won't work - just becomes unresponding again.

After thinking about this, I remembered I had also installed FireFox 3.6.10 after I had gotten rid of the TDSS rootkit redirect virus that was attacking FireFox. This is when I started having the consistent problem of the program freezing every time I tried to upload a photo file.

I uninstalled 3.6.10 and reinstalled 3.5.13 and so far have had no problems uploading photo files. If I find that after several days I end up having the freeze problem I will post here again. Otherwise, this must be a bug in the new version, and I will report it.

You may still be infected or you may need to do a clean reinstall of Firefox if that infection affected Firefox.
See http://kb.mozillazine.org/Standard_diagnostic_-_Firefox#Clean_reinstall

Did you recover from that infection yourself or did you visit a forum that is specialized in malware to ask for help?

See also "Spyware on Windows": http://kb.mozillazine.org/Popups_not_blocked and What to do when searches take you to the wrong search website

Your above posted system details show outdated plugin(s) with known security and stability risks.

1. Shockwave Flash 10.1 r82
2. Next Generation Java Plug-in 1.6.0_14 for Mozilla browsers

Update the Java plugin to the latest version.

• http://java.sun.com/javase/downloads/index.jsp (Java Platform: Download JRE)

Update the Flash plugin to the latest version.

• http://www.adobe.com/software/flash/about/
• http://www.adobe.com/shockwave/welcome/
• http://www.adobe.com/downloads/

Update the Adobe Reader plugin to the latest version.

• http://get.adobe.com/reader/otherversions/