Presario f700 problems

When i put on the system (which runs on vista), the following issues occur:

1 - taskbar refuses to show
2 - cannot access "start" menu
3 - i cannot access the "personcalize" section (when you right click on the desktop and choose "personalize")
4 - when it supposedly goes on "screensaver" mode, the laptop freezes.

There's a fifth problem to mention, but for the time being I cannot remember.

Can anybody put an insight into this, and how to start diagnosing?

Thanks in advance

ok. just an update.

went on kelly's corner and downloaded a program that allowed me to fix the taskbar.

http://www.kellys-korner-xp.com/taskbarplus!.htm

Do you have multiple user accounts on this machine? Try logging in with the second user, if you have that, if that user logon works fine, probability is user profile of your problematic user is damaged.