Problems uploading files to various web browsers

I'm having huge problems with uploading files to various browsers on my MacBook Pro (running Mac Lion OS X 10.7.5)

My default web browser is Google Chrome but I have tried Firefox, Safari and Mail, too, and they're all presenting the same problem.

The problem is that whenever I try to attach a document to an email in Gmail or upload a photo/file to any website - it just doesn't play ball. The web browser then becomes totally unresponsive (not loading new tabs etc.) and I have to Force Quit and start the application running again. When I tried this in Mail, the application actually crashed.

I've figured out a way to get round the problem in Gmail - creating documents in Google Drive or simply dragging documents into the email - but I'm starting an online course soon and I really need to be able to upload documents, files, images etc.

So far I have tried:

• Updating the software on my Mac
• Updating Google Chrome
• Uninstalling and reinstalling Google Chrome
• Signing in and out of Google Chrome
• Deleting all browser history on Google Chrome

I've also figured out that it's not my firewall as I had an unrelated problem with that and it was taken down for around 24 hours to be fixed - I tried again to upload files in this 24 hour window and encountered the same problems.

I'm also having problems with my Windows for Mac - whenever I try to Save or Save As in Word - the programme becomes completely unresponsive, parts of the toolbars at the top white out and I have to Force Quit - hence, why I started using Google Drive to create documents. When I try and Save or Save As in Excel or Powerpoint, these programmes crash too.

I don't know if these problems are related, but I thought it best to bring it up just in case.

Can anyone help me?!