You could try the shift keys. On mine, I have two blank white keys at the bottom left. When I had a similar problem this helped. You also may have to check for rust, dirt, etc, which can cause keys to lock. It may just need a good cleaning and light greasing of key mechanisms. There are many great websites that show step by step instructions on cleaning and maintenance. Hope this helps.
Answers & Comments
You could try the shift keys. On mine, I have two blank white keys at the bottom left. When I had a similar problem this helped. You also may have to check for rust, dirt, etc, which can cause keys to lock. It may just need a good cleaning and light greasing of key mechanisms. There are many great websites that show step by step instructions on cleaning and maintenance. Hope this helps.