Photoshop Question

I have a really quick question to ask. I just re-installed my Photoshop because my computer was messing up and now it's being weird. When I try to load more brushes to use it won't let me. I push the little arrow thing to bring up the menu, but it just stays pressed and won't load the menu. I have no idea why it's doing this. I'm totally annoyed. I tried installing it again, but nope still won't work. I actually feel like making stuff and this happens.

If anyone can help me it would totally be appreciated. Hopefully I haven't messed up my PS. I'm still mesing with it but nothings working. All the other menu's come up fine.

Please help!

Lily*

{Edit:Problem fixed. Thanks to those who helped.}