This has happened sometime ealier already, but now it's worse. I got an email from friend, including approx 10MB attachments (photos). When I try to open that, Thunderbird freezes. The whole PC gets slow. I need to close Thunderbird so I can continue working again. While it's opening the email, I cannot do anything in Thunderbird (just to wait... endlessly). Earlier I fixed this by closing it first, then restarting the PC, but now it didn't work. Also reinstalled, but no help. Also deleted that email from gmail, still no effect. What to do now?

I am using Windows 7. I also tried to open with Antivirus in off mode, no help anyway.