I already knew about why I couldn't send PMs anymore. When I tried to send a PM, the forum told me that I had to be a contributing member to be able to use the PM feature. But thanks for the info. It's not an option for me to become a contributing member right now because I don't have a credit card. Perhaps it's possible to pay via paypal somehow... I'll see what I can find out.
And as for why I want my username changed... My username is "Vishruth" in all the other forums I participate actively in. It would help me to keep my forum username here in sync with my usernames in the other forums I participate in. I am hoping to post more often here. I wouldn't have asked for the change if I didn't plan to post more often here. I don't want to trouble you guys for nothing... really.
EDIT:
Just received Jeremy's mail. My thanks to Jeremy for the change.