pc changes everytime i shut down

hi there im wondering if someone can help my pc is playing up and its something ive never seen before or heard of. I dont know too much about what could have happend as my girlfriend was last on it but everytime I boot up the computer the bottom taskbar has changed to the older windows style (grey version) and my internet connection says renewing ip address and wont connect. I have to do a system restore everytime I load up my pc sometimes several times for it to load up properly with the xp task bar and connection to internet. I wish i could give more info but my girlfriend insists she didnt do anything.