I take it by system restart you mean system restore ?
and what O/s vista/7 ?
Depends on what you have done to try and speed it up, did you try to overclock any of the hardware.
have you tried safe mode ? reboot and press F8 usually
is it just the task bar thats munged up ?
Right click on an empty space on your desktop
click on personalize
click on Windows Color and Appearance
click on Open Classic Windows Properties or any other coloour scheme you like etc
see if that gets you back