Hi someoneboring, Unfortunately this is a unique signature, but the good new is that there are some common causes for uploading issues.

Please try to upload in Safe Mode, this will isolate whether or not an add on is the issue. Diagnose Firefox issues using Troubleshoot Mode

Is there an antivirus that may be preventing the upload? Or a firewall?

Is there a limit to the upload amount on the site or service you are using to upload?

The signature seems to be associated with a Microsoft Windows entity. Please run a virus scan to make sure it is not crashing because malware is detected. Troubleshoot Firefox issues caused by malware

I tried safe mode but it crashed anyway. My antivirus is the same as always as is my firewall. It cant be to do with upload size. Firefox crashes when i try to open the "browse" explorer thingy to select a file to upload.

I ran a virus scan although it didnt detect anything. What i find worrying is that I did it before I went to sleep, it said it was meant to last 4 hours but it only lasted 7 minutes. Skype has similar problems and crashes my computer whenever I try to send a file. I can attach files using internet explorer however.

Separate Issue; Your System Details shows;

Installed Plug-ins

Adobe Shockwave for Director Netscape plug-in, version 12.1.3.153 Adobe Shockwave for Director Netscape plug-in, version 12.1.2.152

Having more than one version of a program may cause issues.

Grab the uninstaller from here: Uninstall Flash Player | Windows Uninstall Flash Player | Mac Then reinstall the latest version.

Update your Flash Player v15.0.0. 239 http://get.adobe.com/flashplayer/ Shockwave Director v12.1.4.154 http://get.adobe.com/shockwave/

Your crash report flagged these programs;

KERNELBASE.dll = Microsoft

ntdll.dll = Microsoft

Perform a System File Check to fix corrupted system files http://www.sevenforums.com/tutorials/1538-sfc-scannow-command-system-file-checker.html