Help! 10.5.5 has been acting up lately on my MacBook Pro!

Question

Here is the deal! Below are a list of bugs that I notice every so often. Please tell me if you have seen any of them before or think there is a way to fix them:
1) Mail shows that there are two messages at the top of the window, where there is only ONE!
2) MobileMe no longer syncs my contacts with my iPhone.
3) The menu bar occasionally doesn't load and I am left with nothing but a dock and desktop.
4) Certain applications that I have always used perfectly, keep telling me that I have never opened them before when I have at each launch.
5) My desktop occasionally will have these random black horizontal lines that disappear as an active window moves over them.
6) Safari downloads will appear in the downloads list and then cannot be removed unless they are relocated from the download folder.
7) The wi-fi connected will not connect sometimes unless I turn my firewall off and then back on.
What's the deal? Most importantly, how do I fix the contact issue with MM?

Answer 1

A few thoughts for diagnosis/testing purposes:
Have you recently run the disk utility and repaired HD and permissions? If not do so.
Boot into the Safe mode - hold down shift key on boot - and see if the problems are still there. Some functions won't work but see if anything odd happens.
Check your startup items. Get rid of them temporarily.
Create a new user account and see if the problems occur with the new account.
Lastly, be sure your backup is up-to-date.