Weird Firefox Problems

Alright this one is a weird problem. Firefox has been serving me well for 2+ years now, but this problem is getting me a tad frustrated.

Everything is running fine, I normally open up Firefox, and I'm signed out of my google homepage, no biggie, sign back in. I go to my bookmarks, they are all gone.....F*CK. I had a 5 month old save of them so not all is lost. I go to some of the sites I had bookmarked but I lost when they all disappeared. I hit Bookmarks>Bookmark this Page and hit ok to save the bookmark. The box where the name of the page is disappears and when I look in my bookmarks there is a bookmark there but it has no name. What is going on here?

Also all little things are acting funny, the cursor to write things is blinking so fast its hardly noticeable. I used to have it when I opened Firefox it would be a fully maximized window, now it starts up as a small window. How do I fix that?

I've tried uninstalling Firefox completely and running CCleaner and I get the same results. I have changed absolutely nothing in the past week. Can anybody help me out here, I just want my old Firefox back. Thanks.

EDIT: I looked into the Error Console and find this line relating to the bookmarks:

Error: uncaught exception: [Exception... "Component returned failure code: 0x8000ffff (NS_ERROR_UNEXPECTED) [nsIRDFService.GetDataSource]" nsresult: "0x8000ffff (NS_ERROR_UNEXPECTED)" location: "JS frame :: chrome://browser/content/bookmarks/addBookmark2.js :: Startup :: line 107" data: no]

Click to expand...

I'm also finding tons of "Not Well Formed" errors in there too. Help me please!

To completely delete your old profile: Start>run> %appdata% and delete the Firefox folder. But before that, if you'd like to retrieve your old bookmarks they should be in a folder called 'bookmarkbackups'.

Wow, there is an auto backup for Firefox, sick. Thank you so much, I will try deleting this whole folder and installing again.

That definitely fixed my bookmarking problem, thank you.