can't acess created accounts

I bought a laptop Sony Vaio one month ago running W Vista Home Premium 32
bits. When I created one administrator account and a standard account a
started to have problems as the acess to menu became impossible because I
switch the different options and nothing happens. The access to the UAC menu
became blocked and some acess to devices like the printer which were used
before creation of two accounts became blocked. I tried to acess the accounts
in safe mode. No way!... Many thanks for any help